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Research Brief 01: Near-Earth Asteroid Target Shortlist for a First Prospecting Mission

Frontier (thefrontier.space) — Research Programme Date: 2026-10-28 Status: Published, v1.1 (schedule section added 29 Oct 2026) Scope: Which near-Earth asteroids (NEAs) a small, low-cost prospecting spacecraft could realistically reach between 2027 and 2032, what we already know about them, and which one Frontier should plan around first.

1. Executive summary

Frontier's first mission will not mine anything. It will prospect: fly to one asteroid, measure what it is made of, how big it is, how fast it spins, and how its surface behaves, and bring that data back by radio. Every serious actor in this field, public or private, has started the same way, and the two private attempts so far (AstroForge's Odin in 2025, Karman+'s slipped first mission) show how unforgiving even that first step is.

The hard constraint is physics. NASA's NHATS accessibility database lists, for every NEA with a usable orbit, the lowest round-trip delta-v (the total change in velocity a spacecraft must produce) and the launch years in which that is achievable [1][2]. Filtering NHATS for launches between 2025 and 2035 and a round-trip delta-v under 7 km/s leaves two groups: dozens of very small bodies (roughly 10–120 m across) that are cheap to reach but almost completely uncharacterised, and only two objects larger than about 70 m [3][4][5][6]. The well-studied, water-bearing asteroids that would be ideal mining targets (Bennu, Ryugu, 2008 EV5, 1996 FG3) have no low-delta-v window in our timeframe [7][8][9][10].

After weighing accessibility, composition, size/spin, and existing knowledge, we recommend:

  • Primary science target: (99942) Apophis. A 340 m S-type asteroid with a NHATS minimum round-trip delta-v of 6.05 km/s for an April 2029 launch [11][12]. It is not water-rich, but it will be the most-observed small body in history: NASA's OSIRIS-APEX, ESA's Ramses, and Karman+'s first mission are all heading there around the April 2029 Earth flyby [13][14][15]. Riding that wave gives a first-time team ground truth to validate its instruments against, a known slow spin (30.6 h) that makes proximity operations easier [12], and data of direct commercial value to every later metal-or-regolith mission.
  • Schedule reality (new in v1.1). Apophis remains the right science target, but an April 2029 launch of a Frontier-built spacecraft is not credible from a late-2026 start with no funding, no engineering team and no partner. The two private teams that have tried this class of mission, with experienced engineers and US$20 million or more, lost or slipped their first flights [19][49][52]. Section 4.4 therefore sets out three architectures: a hosted instrument on a partner's Apophis mission, an own-bus mission to a later window (2000 SG344 in October 2029 or 2025 VD24 in 2030–2032), and a ground-based observing campaign that Frontier can fund and run from 2027 regardless of hardware. The recommended path is the campaign first, a hosted payload if a slot can be secured, and an own-bus mission only when the money and the team exist.
  • Backup target: 2000 SG344. The single most accessible object in NHATS for our window: 3.55 km/s round trip, 370 days, launch 12 October 2029 [16]. It is 20–89 m across, type unknown, and there is unresolved speculation that it could be a leftover Apollo-era rocket stage [16][17]. Its May 2028 close approach (2.9 million km) is an opportunity to settle that from the ground before committing a spacecraft [17].
  • Watch list: 2025 VD24, a newly catalogued 76–341 m Amor asteroid that is the only other NHATS object larger than ~70 m with a sub-7 km/s window in 2025–2035 [5][6][18]. Its composition is completely unknown and it needs telescope time before it can be ranked.

The cost of a first mission of this class is bounded below by AstroForge's sub-$7 million Odin flyby and its planned sub-$10.5 million DeepSpace-2 rendezvous [19][20], and above by NASA's $55 million SIMPLEx cap, which in practice missions have struggled to stay under [21]. Full sample-return missions (OSIRIS-REx, Hayabusa2) cost $1 billion and ¥16.4 billion respectively and are not a realistic model for Frontier [22][23].

2. Selection criteria

We scored candidates on four axes. None of these is a hard cut on its own; together they describe what a first mission can survive.

2.1 Accessibility (delta-v and launch window)

We use NASA's Near-Earth Object Human Space Flight Accessible Targets Study (NHATS) as the reference. NHATS computes, for each object, the minimum total delta-v for a round trip starting from a 400 km circular Earth parking orbit, matching the asteroid's velocity on arrival, departing again, and controlling Earth-entry speed on return, with a stay of at least 8 days [1]. It is built for crewed round trips, so it is an upper bound for a one-way robotic rendezvous. We use it anyway because it is the only consistent, public, regularly recomputed accessibility ranking that also reports launch dates. Our filters: launch 2025–2030 and 2030–2035 (the valid NHATS ranges bracketing 2027–2032), total duration ≤ 360–450 days, delta-v ≤ 6 or 7 km/s [3][4][5][6].

2.2 Composition (what is actually there)

Spectral type is the only remote proxy for composition. C-, B- and Cb-types (Bennu, Ryugu, 2008 EV5, 1996 FG3) are associated with carbonaceous chondrite material and hydrated minerals; sample analysis of Ryugu found a CI-chondrite-like bulk composition [24] and about 6.8 wt% water, lower than the 13–20 wt% of CI meteorites on Earth, with interlayer water apparently lost to space [25]. Bennu samples contained a full evaporite salt sequence, 14 of the 20 protein amino acids, all five nucleobases and abundant ammonia [26]. S/Sq-types (Apophis, Torifune) are dry, ordinary-chondrite-like rock [27]. Genuine metallic (M-type) NEAs are rare and 2011 UW158, the most-hyped "platinum" candidate, turned out by radar to have no more metal than an average rocky asteroid [28].

2.3 Size and spin (can you operate near it?)

Below roughly 100 m most asteroids are not rubble piles but monoliths spinning far faster than the 2.2 h cohesionless limit. Three of the smallest accessible bodies illustrate the problem: 1998 KY26 is 11 ± 2 m across and rotates every 5.35 minutes [29]; 2022 OB5 rotates every 1.54 minutes [30]; 2011 UW158 (300 × 600 m) rotates every 36.6 minutes [28]. On 2022 OB5, centrifugal force at the surface would be nearly 100 times the asteroid's gravity [30]. A first mission should prefer a body with a spin period of hours, not minutes.

2.4 Knowledge (how much has already been measured?)

Radar shape models, thermal inertia, albedo and a visible/near-infrared spectrum turn a dot in a catalogue into an engineering target. Objects with another spacecraft en route are worth extra: Frontier's measurements can be validated against theirs, and vice versa.

3. Ranked shortlist

Delta-v is the NHATS minimum round-trip value, in km/s. "Next window" is the NHATS launch date for that minimum, or "none ≤ 7 km/s" where the object does not appear in any 2025–2035 NHATS filter at ≤ 7 km/s. Diameters and types are from JPL's Small-Body Database (SBDB) unless noted.

Rank Object Δv (km/s) Window Type Diameter Spin Why it ranks here
1 (99942) Apophis 6.049, 354 d Launch 2029-04-11 [11] Sq (LL-chondrite-like) [12][27] 340 ± 40 m [12] 30.56 h [12] Only large, well-characterised body with a sub-7 km/s window in 2027–2032. Three other missions arriving 2029–2030 give ground truth [13][14][15]. Dry.
2 2000 SG344 3.549, 370 d Launch 2029-10-12 [16] Unknown 20–89 m (NHATS) [16] Unknown Cheapest target in the entire NHATS catalogue for our window. Possibly artificial (S-IVB stage) [17]. Observable May 2028.
3 2025 VD24 6.813 (2025–30), 6.139 (2030–35) [5][6] Within 2025–2035 (date not published in filter output) Unknown 76–341 m (NHATS) [5]; H = 21.79, Amor, OCC 0 [18] Unknown Only other ≥ 70 m object accessible under 7 km/s in our window. Needs spectroscopy.
4 (341843) 2008 EV5 6.291, 362 d Launch 2024-06-24 (past); none ≤ 7 km/s in 2025–2035 [9] C-type, CI-like [31] 400 ± 50 m (radar) [32] 3.725 h [32] Best-understood low-Δv C-type; was NASA ARM baseline [33]. Window missed; optical observing window Nov 2026–Apr 2027 for ground follow-up [9].
5 (101955) Bennu 6.995, 362 d Launch 2036-03-21 [7] B-type [34] 484 m [34] 4.296 h [34] Fully characterised by OSIRIS-REx; sample-proven volatiles and organics [26]. Next window is after our horizon.
6 (162173) Ryugu 8.248, 370 d Launch 2020 (past); 90-day fast transfer 2033-12-10 at 11.96 km/s [8] Cb [35] 896 m [35] 7.63 h [35] Hayabusa2 ground truth, ~6.8 wt% water [25]. Not accessible cheaply in our window.
7 (175706) 1996 FG3 11.274, 450 d Launch 2024-11-15 (past) [10] C (SMASS) [36]; binary [37] 1.20 ± 0.36 km [36] 3.59 h [36] Scientifically excellent binary C-type but NHATS round-trip Δv is far too high.
8 1998 KY26 7.845, 442 d Launch 2024 (past) [38] Unknown; high albedo 0.52 suggests bright/E-like material [29] 11 ± 2 m [29] 5.35 min [29] Hayabusa2 will rendezvous in 2031 [39]. Too small and too fast-spinning for a first commercial mission.
— 2022 OB5 3.517, 362 d Launch 2025-01-18 (past) [40] Unknown (suspected metallic, unconfirmed) [41] 2.8–12 m (NHATS) [40] 1.54 min [30] AstroForge's Odin target. Excluded: spin makes surface operations impractical.
— (436724) 2011 UW158 Not in NHATS [42] — Assumed S; radar shows ordinary metal content [28] 300 × 600 m (radar) [28] 0.611 h [43] Excluded: "platinum asteroid" claims unsupported by radar; not NHATS-accessible.

Observations on the table:

  • The accessible set and the well-known set barely overlap. In 2025–2030, 37 objects clear NHATS at ≤ 6 km/s and ≤ 360 days, and every one of them has H ≥ 24.1, i.e. is smaller than roughly 120 m [3]. In 2030–2035 the equivalent list is 34 objects, again all tiny [4]. Raising the cut to 7 km/s and restricting to H ≤ 22 (roughly ≥ 70 m) leaves exactly two objects: Apophis and 2025 VD24 [5][6].
  • The famous C-types all missed their windows. 2008 EV5's minimum-Δv launch was June 2024 [9]; 1996 FG3's was November 2024 [10]; Ryugu's was 2020 [8]; Bennu's next is 2036 [7].
  • Small does not mean easy. The three best-measured sub-50 m objects (KY26, 2022 OB5, UW158) all spin in minutes.

4. Recommendation

4.1 Primary: Apophis, launch window April 2029

Case for. Apophis is 340 ± 40 m across with a radar shape model, measured albedo (0.35), thermal inertia (50–500 J m⁻² s⁻½ K⁻¹) and a 30.56 h rotation period [12]. Its spectrum has been matched to LL ordinary chondrites with better than 89% likelihood [27]. On 13 April 2029 it passes about 32,000 km above Earth's surface [15]. ESA's Ramses is contracted (OHB Italia, ESA contract signed October 2024 for €63 million of preparatory work) to launch in April 2028 and arrive in February 2029 [14][44]; NASA's OSIRIS-APEX, the re-tasked OSIRIS-REx spacecraft, arrives after the flyby [13]; Karman+ has publicly moved its first mission to Apophis with a mid-2028 launch and 2030 rendezvous, calling it a "target of opportunity" while stating it would prefer a water-rich C-type [15][45]. NHATS gives a 6.049 km/s round-trip solution launching 11 April 2029 with a 49-day outbound leg [11].

Case against. It is dry. Karman+'s own description is "a dry ball of dirt" [45]. A Frontier mission to Apophis measures the regolith, strength and metal/silicate ratio of an S-type, which is relevant to structural-material and oxygen-from-silicate use cases, not to water. The launch window is tight and shared; the 2029 approach geometry is a one-off.

Why it still wins as the science target. For a first mission the value is in de-risking the spacecraft, navigation, autonomy, and instrument calibration against independent data. No other target in our window offers that.

Why it does not win as a Frontier-built spacecraft mission. The window is 30 months from the date of this revision. ESA's Ramses needed a preparatory contract in October 2024 and a build contract in February 2026 to make a spring 2028 launch [44][55], and AstroForge, with a funded team, built Odin in ten months only by accepting a flyby with a minimal payload and lost it within weeks [19][49]. Frontier has neither a team nor a spacecraft budget today. The realistic ways to put Frontier instruments or Frontier-funded science at Apophis in 2029 are set out in §4.4, and none of them is an own-bus launch on 11 April 2029.

4.2 Backup: 2000 SG344, launch window October 2029

Case for. The lowest round-trip delta-v in NHATS for our window, 3.55 km/s over 370 days, with over 3.3 million viable trajectories in the database [16]. Orbit is nearly identical to Earth's (a = 0.977 au, e = 0.067, i = 0.11°) [17]. May 2028 close approach at 2.93 million km, reaching magnitude 19, gives a ground-based characterisation opportunity 17 months before launch [17].

Case against. Size known only to within a factor of two (NHATS 20–89 m) [16]; no spectrum; orbit condition code 3 on a 507-day arc [46]; and the unresolved possibility that it is an Apollo S-IVB stage rather than an asteroid [17]. Also, a body that small is likely to be a rapid rotator.

Decision rule. If 2028 observations show a natural body with a rotation period above ~1 hour, SG344 becomes the fallback for any slip past the Apophis window.

4.3 Watch list: 2025 VD24

An Amor with a 5,610-day observation arc and condition code 0 [18], 76–341 m across by NHATS estimate, reachable under 7 km/s in both the 2025–2030 and 2030–2035 ranges [5][6]. There is no published spectrum, albedo or spin. Frontier should commission or request lightcurve and spectral observations during its NHATS optical window (28 October 2026 to 3 May 2027) [6]. If it proves to be a slow-spinning C-type it would displace Apophis on composition grounds, and because its 2030–2035 window (6.14 km/s) [6] falls after the earliest date an own-bus Frontier mission could plausibly fly, it is in practice the leading candidate for that architecture.

4.4 Mission architecture options and schedule reality

This section was added in v1.1 to reconcile the target ranking above with the project's actual starting position, as stated in Frontier's investor documents: one founder, no engineers, no signed partners and no mission funding as of October 2026. The ranking in §3 is a statement about asteroids. This section is a statement about what Frontier can do with it, and by when.

The schedule problem, stated plainly. The Apophis NHATS window opens 11 April 2029 [11]. Ramses, a fully funded ESA mission with a prime contractor, needed a preparatory contract in October 2024 and a €81.2 million build contract in February 2026 to make a spring 2028 launch [44][55]; that is a three-and-a-half-year run at an agency's pace, started two years before Frontier's first research brief existed. AstroForge's Odin went from start to launch in about ten months and under US$7 million, but as a camera-only flyby that was lost to communication and deployment failures within weeks [19][49][50]. Karman+, with a US$20 million seed round and an experienced team, slipped its first launch from early 2027 to mid-2028 because a propulsion vendor could not deliver [45][53]. A Frontier spacecraft on the April 2029 window would need a funded team, a bus vendor and a launch contract in place by roughly mid-2027. None of those exists and no scenario in Frontier's own financial model funds flight hardware below the US$10 million raise level. We therefore treat an own-bus Apophis launch in April 2029 as not credible and plan around it rather than toward it.

Architecture A: own spacecraft. A 100–200 kg bus with a camera and, if budget allows, a visible/near-infrared spectrometer, on a rideshare launch, in the AstroForge/Karman+ cost class.
Pros Full control of target, instruments and data; the only architecture that produces a Frontier-operated spacecraft and the operational experience that goes with it.
Cons Highest cost and highest failure rate: both private first attempts to date have failed or slipped [19][45][49]. Requires an engineering team, a bus vendor and 24–36 months of build time after funding. Apophis 2029 is out of reach; realistic targets are 2000 SG344 (launch 12 October 2029, 3.55 km/s) [16] or 2025 VD24 (2030–2035 window, 6.14 km/s) [6].
Rough cost US$10–20 million including launch, bounded by DeepSpace-2 (under US$10.5 million) and Karman+ (under US$20 million per mission) [51][52].
What has to be true, by when Phase A concept study complete and a bus vendor selected by end 2027; US$10 million-class mission funding and a mission lead plus systems engineer hired by early 2028 for an October 2029 SG344 launch, or by early 2029 for a 2030–2032 VD24 launch; 2028 ground observations confirming SG344 is a natural, slow-rotating body (§4.2), or 2027 observations characterising VD24 (§4.3).

Architecture B: hosted payload or instrument on a partner's Apophis mission. Frontier funds or supplies an instrument, a deployable, or a data product that flies on another team's spacecraft.
Pros The only architecture that can put Frontier-funded science at Apophis in 2029. Cost is an order of magnitude lower than a bus. Partners take the navigation, communications and operations risk that killed Odin. Produces data validated against the host's own instruments.
Cons Frontier does not control the manifest, the schedule or the data policy; slots may not exist. Ramses' payload complement, including its two CubeSats, was selected by 2025 and passed critical design review in early 2026 [55][56], so a new hardware item on Ramses is very unlikely. OSIRIS-APEX is an existing spacecraft with a fixed instrument suite [13]. Karman+ is a private company with its own commercial objectives and has not announced a hosted-payload offering [45]. The realistic forms of this architecture are therefore a funded science investigation or data-analysis role with one of the three teams, a contribution to the ground segment, or an instrument on a later partner mission to a different target, rather than a Frontier box bolted to a 2029 spacecraft. NASA's February 2024 Apophis innovation listening workshop shows the agency has solicited outside ideas for the encounter, which is the channel through which such a role would be proposed [60].
Rough cost US$0.5–3 million for an instrument-class contribution or a funded participating-scientist role; Frontier's pitch deck reserves US$1.5 million for a partner co-funding or hosted-payload deposit at the US$10 million raise level. These figures are assumptions pending a partner conversation.
What has to be true, by when A signed letter of intent with a mission team or a university group that already has an Apophis role, by mid-2027, because payload manifests for a 2028 launch are closed by then; a NZ or international university partner with an existing planetary-science instrument heritage; and funding at the US$1 million level to pay for the Phase A study that any host would want to see first.

Architecture C: ground-based observation campaign first. Frontier funds telescope time, data reduction and publication on the three candidate asteroids, coordinated with the International Asteroid Warning Network's Apophis campaign, which plans a 2027–2028 pre-encounter phase focused on rotation state and visible spectra and a 2029 close-approach phase with citizen-science participation [57]. The 2024 and 2025 Apophis workshops explicitly recommended coordinated use of the broadest possible set of Earth-based telescopes, including small apertures [58][59].
Pros Can start in 2027 with the money Frontier is actually raising. Directly answers the open questions in §7 that decide between SG344 and VD24 (is SG344 natural? what is VD24?). Every result is publishable and citable, which is what a prospective host or agency partner evaluates. No hardware risk. Builds the relationships (IAWN, university observers) that Architecture B depends on.
Cons Not a spacecraft. Remote characterisation cannot measure mass, mechanical properties or surface composition at the level a rendezvous can (§5). 2025 VD24's optical window closes 3 May 2027 [6] and SG344's best apparition is May 2028 [17], so the campaign has hard dates that cannot slip.
Rough cost US$20,000–150,000 across the three raise scenarios in Frontier's pitch deck, covering telescope-time applications or purchased time on 1–2 m class instruments, a part-time observer or graduate student, and data reduction.
What has to be true, by when Telescope time requested or purchased by January 2027 for the VD24 window (closes 3 May 2027) [6]; a named observer or university collaborator by the same date; SG344 lightcurve and spectral observations scheduled for the May 2028 apparition [17]; results published as a Frontier research brief within three months of each campaign.

Recommended sequence. C, then B, then A. Run the ground campaign in 2027–2028 because it is affordable now and because its results decide everything downstream. Use those results and the Phase A study to approach the Apophis teams and a university partner for a hosted role before mid-2027 manifests close. Commit to an own-bus mission only when a target has been characterised, a bus vendor is under contract and US$10 million-class funding is in hand, which on current plans means a 2030–2032 launch to 2025 VD24 or, if the 2028 observations are favourable, the October 2029 window to 2000 SG344. Apophis stays the primary science target throughout: the 2029 encounter is the calibration event for every instrument Frontier will ever fly, whether Frontier's hardware is there or not.

5. What a first prospecting mission would measure

The commercial question is: how much usable material is here, and can hardware survive touching it? Based on what OSIRIS-REx, Hayabusa2, and the two private programmes have prioritised:

  1. Shape, volume and mass. Camera-based shape model plus radio-tracking during close approaches to get mass, hence bulk density and porosity. Bennu's 1.19 g/cm³ and Ryugu's 1.19 g/cm³ [34][35] say "rubble pile" and set expectations for anchoring.
  2. Spin state. Period and pole, measured early, because they govern every subsequent operation (see §2.3). Hayabusa2's Torifune flyby on 5 July 2026, at ~5 km/s relative speed, confirmed the body is a contact binary from optical and thermal-infrared images alone [47][48]; a flyby can do this cheaply but a rendezvous is needed for everything below.
  3. Surface composition. Visible/near-infrared spectrometer for the 0.7 µm and 2.7–3.0 µm hydration features; thermal-infrared for thermal inertia (boulder vs. fine regolith). AstroForge's DeepSpace-2 flies only a high-resolution monochrome camera on a 200 kg bus with 60 kg of xenon, which is the minimum viable payload for shape and surface texture, not composition [20].
  4. Mechanical properties. A low-energy contact or a deployed test package, as Karman+ plans at Apophis ("deploy our tests on the surface") [45]. Volatile yield cannot be measured without disturbing the surface.
  5. Autonomy and link budget. Odin was lost within weeks of launch to communication and probable solar-array deployment problems [49][50]. Demonstrating that a sub-$10 million spacecraft can simply stay alive and talk from millions of kilometres away is itself a mission objective.

6. Cost envelope

Figures below are as reported; they are not directly comparable (different scopes, years, and currencies).

Reference mission Reported cost Scope Source
AstroForge Odin (2025 flyby, 100–120 kg) under $7 million total mission incl. rideshare launch [19]
AstroForge DeepSpace-2 (Q4 2026 / 2027 rendezvous, 200 kg) under $10.5 million including launch [51]
Karman+ first mission "under $20 million" per mission; $20 million seed round, Feb 2025 development [52][53]
NASA SIMPLEx class $55 million cap excluding launch; Lunar Trailblazer rose to ~$72 million development + ops [21]
ESA Ramses (Apophis) €63 million preparatory contract (Oct 2024) partial [44]
JAXA Hayabusa2 ¥16.4 billion (2010 estimate, excl. launcher) development [23]
NASA OSIRIS-REx $1.02 billion lifetime (Planetary Society) full mission [22]

A Frontier prospecting mission should be designed to the AstroForge/Karman+ envelope ($10–20 million) and judged against the SIMPLEx experience: the cap is achievable only with ruthless scope control. The ground campaign (Architecture C, §4.4) costs two orders of magnitude less and is the only line item Frontier can fund from its first raise.

7. Open questions

  1. Is 2000 SG344 an asteroid? The S-IVB hypothesis has not been publicly resolved [17]. May 2028 spectroscopy would settle it.
  2. What is 2025 VD24? No physical data beyond H = 21.79 [18].
  3. One-way delta-v. NHATS is round-trip. Frontier needs its own trajectory study for one-way rendezvous (and for low-thrust electric propulsion, which DeepSpace-2 uses [20]) to see which additional NHATS objects become viable.
  4. What did Hayabusa2 learn at Torifune? About 300 MB were collected and only ~25 MB had been downlinked by late July 2026 [48]. Results through 2027 will refine what a fast flyby can and cannot determine.
  5. Will Apophis get crowded? Three spacecraft plus Frontier around one 340 m body require coordination; the conjunction and navigation implications are not yet public.
  6. Is 2008 EV5's 0.48 µm feature real? Follow-up spectra were too noisy to confirm or deny the CI-chondrite match [31][54]. Its Nov 2026–Apr 2027 observing window is the next chance [9].
  7. How many NHATS tiny objects are monoliths? If most sub-100 m NEAs spin in minutes, the "cheap" end of the NHATS list may be almost entirely unusable for surface operations.
  8. Is there any hosted slot at Apophis? Ramses' payload is fixed and OSIRIS-APEX is already flying; whether Karman+ or any of the Apophis science teams would take a funded instrument, a participating-scientist role or a ground-segment contribution has not been asked. This is the first partner conversation Frontier should have (§4.4, Architecture B).

8. References

  1. NASA CNEOS, "NHATS – Near-Earth Object Human Space Flight Accessible Targets Study." https://cneos.jpl.nasa.gov/nhats/
  2. NASA JPL SSD API, NHATS endpoint (object and filtered queries). https://ssd-api.jpl.nasa.gov/nhats.api
  3. NHATS filtered query, Δv ≤ 6 km/s, duration ≤ 360 d, launch 2025–2030, H ≤ 26, OCC ≤ 7 (37 objects; retrieved 2026-10-27). https://ssd-api.jpl.nasa.gov/nhats.api?dv=6&dur=360&stay=8&launch=2025-2030&h=26&occ=7
  4. NHATS filtered query, same limits, launch 2030–2035 (34 objects). https://ssd-api.jpl.nasa.gov/nhats.api?dv=6&dur=360&stay=8&launch=2030-2035&h=26&occ=7
  5. NHATS filtered query, Δv ≤ 7 km/s, duration ≤ 450 d, launch 2025–2030, H ≤ 22 (2 objects: Apophis, 2025 VD24). https://ssd-api.jpl.nasa.gov/nhats.api?dv=7&dur=450&stay=8&launch=2025-2030&h=22&occ=7
  6. NHATS filtered query, Δv ≤ 7 km/s, duration ≤ 450 d, launch 2030–2035, H ≤ 22 (1 object: 2025 VD24). https://ssd-api.jpl.nasa.gov/nhats.api?dv=7&dur=450&stay=8&launch=2030-2035&h=22&occ=7
  7. NHATS object record, 101955 Bennu. https://ssd-api.jpl.nasa.gov/nhats.api?des=101955
  8. NHATS object record, 162173 Ryugu. https://ssd-api.jpl.nasa.gov/nhats.api?des=162173
  9. NHATS object record, 2008 EV5. https://ssd-api.jpl.nasa.gov/nhats.api?des=2008%20EV5
  10. NHATS object record, 1996 FG3. https://ssd-api.jpl.nasa.gov/nhats.api?des=1996%20FG3
  11. NHATS object record, 99942 Apophis. https://ssd-api.jpl.nasa.gov/nhats.api?des=99942
  12. JPL SBDB, 99942 Apophis physical parameters (Brozović et al. 2018, Icarus 300; Pravec et al. 2014, Icarus 233; Licandro et al. 2016, A&A 585; Binzel et al. 2009, Icarus 200). https://ssd-api.jpl.nasa.gov/sbdb.api?sstr=99942&phys-par=1
  13. NASA Science, "OSIRIS-APEX." https://science.nasa.gov/mission/osiris-apex/
  14. Wikipedia, "Ramses (spacecraft)" (launch April 2028 on H3, arrival February 2029). https://en.wikipedia.org/wiki/Ramses_(spacecraft)
  15. Karman+, "Missions" (Mission 1 – 99942 Apophis, Corvus, launch mid-2028, rendezvous 2030). https://www.karmanplus.com/missions/
  16. NHATS object record, 2000 SG344. https://ssd-api.jpl.nasa.gov/nhats.api?des=2000%20SG344
  17. Wikipedia, "2000 SG344" (size 15–70 m, S-IVB speculation, May 2028 approach at 2.93 million km, 2008 Orion study). https://en.wikipedia.org/wiki/2000_SG344
  18. JPL SBDB, 2025 VD24. https://ssd-api.jpl.nasa.gov/sbdb.api?sstr=2025%20VD24&phys-par=1
  19. CNN (via KVIA), "This asteroid-hunting company could make history with its first deep space mission," 25 Feb 2025 (mission cost under $7 million, built in ten months). https://kvia.com/cnn-other/2025/02/25/this-asteroid-hunting-company-could-make-history-with-its-first-deep-space-mission-the-ceo-is-terrified/
  20. AstroForge, "DeepSpace-2" (200 kg bus, 60 kg xenon, monochrome camera, Q4 2026 launch, metallic target). https://www.astroforge.com/deepspace-2
  21. Spaceflight Now, "NASA's first interplanetary smallsats may struggle to stay under cost caps," 5 Aug 2019. https://spaceflightnow.com/2019/08/05/nasas-first-interplanetary-smallsats-may-struggle-to-stay-under-cost-caps/
  22. The Planetary Society, "Cost of OSIRIS-REx." https://www.planetary.org/space-policy/cost-of-osiris-rex
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  25. Carbonne, D. et al. (2023), Hayabusa2 Sample Return Symposium abstract S23-02 (Ryugu 6.8 wt% water vs. CI 13–20 wt%). https://curation.isas.jaxa.jp/symposium/abstract/2023/S23-02_Carbonne.pdf
  26. University of Arizona LPL, "Asteroid Bennu Comes From a Long-lost Salty World With Ingredients For Life," 29 Jan 2025 (McCoy et al., Nature; Glavin et al., Nature Astronomy). https://lpl.arizona.edu/news/spotlight/asteroid-bennu-comes-long-lost-salty-world-ingredients-life
  27. Reddy, V. et al. (2018), "Surface Composition of (99942) Apophis," AJ 155, 140. https://arxiv.org/abs/1803.05375
  28. Wikipedia, "(436724) 2011 UW158" (Arecibo 300 × 600 m, 0.611 h rotation, radar metal content, platinum claims). https://en.wikipedia.org/wiki/(436724)_2011_UW158
  29. Santana-Ros, T. et al. (2025), "Hayabusa2 extended mission target asteroid 1998 KY26 is smaller and rotating faster than previously known," Nature Communications 16, 8275. https://www.nature.com/articles/s41467-025-63697-4
  30. Universe Today, "Asteroid 2022 OB5 spins too fast for current prospectors" (Alarcon et al. 2026, Icarus; 1.542 min period). https://www.universetoday.com/articles/asteroid-2022-ob5-spins-too-fast-for-current-prospectors-highlighting-the-divide-between-accessible
  31. Reddy, V. et al. (2012), "Composition of near-Earth Asteroid 2008 EV5: Potential target for robotic and human exploration," Icarus 221. https://arxiv.org/abs/1209.1207
  32. JPL SBDB, 341843 (2008 EV5) physical parameters (Busch et al. 2011, Icarus 212; Galad et al. 2009). https://ssd-api.jpl.nasa.gov/sbdb.api?sstr=2008%20EV5&phys-par=1
  33. Perna, D. et al. (2016), "An investigation of the low-ΔV near-Earth asteroids (341843) 2008 EV5 and (52381) 1993 HA." https://arxiv.org/abs/1610.00896
  34. JPL SBDB, 101955 Bennu physical parameters (Daly et al. 2020; Hergenrother et al. 2019; Clark et al. 2011). https://ssd-api.jpl.nasa.gov/sbdb.api?sstr=101955&phys-par=1
  35. JPL SBDB, 162173 Ryugu physical parameters (Watanabe et al. 2019; Sugita et al. 2019). https://ssd-api.jpl.nasa.gov/sbdb.api?sstr=162173&phys-par=1
  36. JPL SBDB, 175706 (1996 FG3) physical parameters. https://ssd-api.jpl.nasa.gov/sbdb.api?sstr=1996%20FG3&phys-par=1
  37. de León, J. et al. (2013), "Ultraviolet to near-infrared spectroscopy of the potentially hazardous, low delta-V asteroid (175706) 1996 FG3," A&A 556. https://www.aanda.org/articles/aa/full_html/2013/07/aa21677-13/aa21677-13.html
  38. NHATS object record, 1998 KY26. https://ssd-api.jpl.nasa.gov/nhats.api?des=1998%20KY26
  39. Hirabayashi, M. et al. (2021), "Hayabusa2 Extended Mission: New Voyage to Rendezvous with a Small Asteroid Rotating with a Short Period." https://arxiv.org/abs/2104.08660
  40. NHATS object record, 2022 OB5. https://ssd-api.jpl.nasa.gov/nhats.api?des=2022%20OB5
  41. Wikipedia, "2022 OB5" (suspected M-type, composition not known). https://en.wikipedia.org/wiki/2022_OB5
  42. NHATS object query for 2011 UW158 returns "specified NHATS object not found." https://ssd-api.jpl.nasa.gov/nhats.api?des=2011%20UW158
  43. JPL SBDB, 436724 (2011 UW158). https://ssd-api.jpl.nasa.gov/sbdb.api?sstr=2011%20UW158&phys-par=1
  44. SpaceNews, ESA Ramses preparatory contract with OHB Italia, €63 million, October 2024. https://spacenews.com/?p=507349
  45. Karman+, "K+ Mission 1 -> 99942 Apophis," 21 Jul 2026. https://www.karmanplus.com/k-mission-1-99942-apophis/
  46. JPL SBDB, 2000 SG344 (condition code 3, 507-day arc). https://ssd-api.jpl.nasa.gov/sbdb.api?sstr=2000%20SG344&phys-par=1
  47. Wikipedia, "98943 Torifune" (= 2001 CC21; flyby 5 July 2026; contact binary; 840 × 340 m). https://en.wikipedia.org/wiki/98943_Torifune
  48. The Planetary Society, "Hayabusa2 flies by asteroid Torifune," Planetary Radio, 2026. https://www.planetary.org/planetary-radio/2026-hayabusa2-torifune
  49. Space.com, "Hope is all but lost for private asteroid probe in deep space," March 2025. https://www.space.com/space-exploration/private-spaceflight/hope-is-all-but-lost-for-private-asteroid-probe-in-deep-space-the-chance-of-talking-with-odin-is-minimal
  50. Space.com, "'I think we all know that hope is fading.' Private Odin asteroid probe is tumbling in space." https://www.space.com/space-exploration/private-spaceflight/i-think-we-all-know-that-hope-is-fading-private-odin-asteroid-probe-is-tumbling-in-space
  51. Orange County Business Journal, "AstroForge prepares second asteroid mission" (DeepSpace-2 under $10.5 million including launch). https://www.ocbj.com/technology/astroforge-prepares-second-asteroid-mission/
  52. The Space Review, "The new wave of asteroid mining ventures" (Karman+ missions budgeted under $20 million). https://www.thespacereview.com/article/4955/1
  53. Space Insider, "Karman+ Raises $20 Million to Mine Asteroids," 21 Feb 2025. https://spaceinsider.tech/2025/02/21/karman-raises-20-million-to-mine-asteroids-to-supply-the-space-economy/
  54. Alí-Lagoa, V. et al. (2013), "Thermophysical properties of near-Earth asteroid (341843) 2008 EV5 from WISE data." https://arxiv.org/abs/1310.6715
  55. European Spaceflight, "ESA Awards OHB a €81.2 Million Contract for Ramses Asteroid Probe," February 2026 (build contract; critical design review concluded; launch spring 2028, arrival February 2029). https://europeanspaceflight.com/esa-awards-ohb-a-e81-2-million-contract-for-ramses-asteroid-probe/
  56. Space.com, "Europe wants to land a tiny spacecraft on the infamous asteroid Apophis in 2029" (Ramses CubeSat lander selection). https://space.com/space-exploration/asteroid-comet-missions/europe-wants-to-land-a-tiny-spacecraft-on-the-infamous-asteroid-apophis-in-2029
  57. International Asteroid Warning Network, "Apophis Observing Campaign" (2027–2028 pre-encounter phase; 2029 close-approach phase; small-telescope participation). https://iawn.astro.umd.edu/obscamp/Apophis/
  58. ESA/ESTEC, "Apophis T-5 Years" workshop programme v4.1, April 2024. https://www.cosmos.esa.int/documents/11661626/0/Apophis_T-5+Program_v4.1.pdf
  59. EPSC-DPS 2025 abstract 198, findings of the Apophis T-4 Years workshop, Tokyo, April 2025 (recommendation for coordinated Earth-based observations across all wavelengths). https://meetingorganizer.copernicus.org/EPSC-DPS2025/EPSC-DPS2025-198.html
  60. SpacePolicyOnline, "Apophis 2029 Innovation Listening Workshop," NASA, 7 February 2024. https://spacepolicyonline.com/events/apophis-2029-innovation-listening-workshop-nasa-feb-7-2024-dc-900-am-et/

Additional context consulted: Hayabusa2 Torifune flyby overview (arXiv:2604.08832, https://arxiv.org/abs/2604.08832); Phys.org, "Another success for Hayabusa 2 as it completes a flyby of asteroid Torifune" (https://phys.org/news/2026-07-success-hayabusa-flyby-asteroid-torifune.html); Landau & Strange, "Near-Earth Asteroids Accessible to Human Exploration" (https://kiss.resources.caltech.edu/uploads/2026/09/asteroids-classification-and-study-near-earth-asteroid-accessible-to-human-exploration-landau-strange-2.pdf); NASA NTRS, "The Mission Accessibility of Near-Earth Asteroids" (https://ntrs.nasa.gov/api/citations/20150009390/downloads/20150009390.pdf).

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