Image of 101955 Bennu captured by the OSIRIS-REx spacecraft in 2020.

The exploration of asteroids involves the study of these small, rocky bodies within the Solar System. Since the discovery of 1 Ceres, which is now classified as a dwarf planet, asteroids have garnered significant interest from the astronomers. These celestial objects are seen as key to understanding the early Solar System and hold potential for future resource utilization. Ongoing and planned missions aim to mine asteroids for valuable materials and further investigate their contributions to our planetary neighborhood.

Technical requirements

edit

The technical requirements for missions to explore asteroids involve several key considerations and advanced technologies. Efficient propulsion systems are essential for navigating the vast distances of space. Chemical propulsion is commonly used for initial launch and major trajectory changes,[1] while ion propulsion provides efficient long-duration thrust for deep-space maneuvers.[2] Sufficient fuel reserves are crucial for trajectory adjustments, course corrections, and potential return trips, with the amount needed varying based on the specific asteroid's distance and orbital characteristics.[3][4][5]

Detailed trajectory planning is necessary for optimizing fuel use and mission duration, often employing gravity assists from planets to boost the spacecraft’s speed and alter its trajectory without expending additional fuel. Accurate navigation systems are required to guide the spacecraft to the asteroid, utilizing star trackers,[6] inertial measurement units,[7] and onboard computers capable of processing real-time navigational data.[8]

Maintaining communication with Earth over vast distances necessitates high-gain antennas, which ensure the transmission of scientific data and telemetry between the spacecraft and mission control.[9] A reliable power supply, often provided by solar panels[10] or radioisotope thermoelectric generators (RTGs),[11] is essential to power the spacecraft's instruments and systems throughout the mission. Additionally, asteroid missions require a suite of scientific instruments tailored to study the asteroid's composition, structure, and other characteristics, providing valuable data for both scientific research and potential future resource utilization.

Flyby missions

edit

1970s

edit

Pioneer 10

edit

In August 1972, Pioneer 10 incidentally flew by an unnamed asteroid en route to Jupiter, marking the first encounter of a man-made object with an asteroid. Later that year, in December, it flew past 307 Nike.[12]

1990s

edit

Galileo

edit
 
Image of Gaspra. Colors are exaggerated

On October 29, 1991, at 22:37 UTC, the Galileo spacecraft conducted a flyby of the S-type asteroid 951 Gaspra, passing at a distance of 1,604 km (997 mi). During the flyby, Galileo captured 57 images of Gaspra, with the closest approaches reaching within 5,300 km (3,300 mi). The highest-resolution images obtained have a resolution of 54 meters per pixel (177.16 ft).[13][14]

During the flyby of Gaspra, Galileo measured the asteroid's surface area to be approximately 525 km2, comparable to the size of Hong Kong or Guam.[15] Galileo studied Gaspra and discovered that its surface composition is primarily made up of olivine and pyroxene.[16] Additionally, Galileo found that Gaspra's surface is relatively flat, with one of the largest areas being approximately 200 m (660 ft), the same diameter as Pontikonisi in Greece.[17]

 
Image of Ida and Dactyl

On August 28, 1993, Galileo visited another S-type asteroid, 243 Ida. It discovered that Ida's surface was heavily cratered and primarily composed of olivine and pyroxene.[18][19] Additionally, Galileo found that Ida was split into two sections, with the top, ball-like section named Pola Regio. This formation was possibly the result of a previous impact from a larger body that did not travel fast enough to disrupt Ida's shape. Additionally, Galileo discovered the first asteroid moon, Dactyl.[20]

NEAR Shoemaker

edit

On June 27, 1997, the NEAR Shoemaker spacecraft flew by asteroid 253 Mathilde en route to 433 Eros. NEAR discovered Mathilde was heavily cratered, with the largest crater being roughly 33.4 km (20.8 mi) in diameter, roughly the same diameter as the island of Vieques in Puerto Rico.[21] NEAR discovered that Mathilde is predominantly composed of carbonaceous material, similar to CI1 or CM2 carbonaceous chondrite meteorites, with a surface rich in phyllosilicate minerals.[22][23]

 
Image of Eros from NEAR Shoemaker

On December 20, 1998, NEAR performed an orbital insertion to enter orbit around 433 Eros. However, the insertion was immediately halted, and the spacecraft entered safe mode. During the failed orbital insertion, NEAR consumed 37 kg of its total fuel. The original mission had planned for four burns after insertion around Eros. However, due to the spacecraft’s unexpected condition, these subsequent burns were impossible to execute effectively.[24][25]

On February 14, 2000, NEAR successfully entered orbit around Eros, marking the first time a spacecraft had inserted an orbit around such an asteroid. Prior to this, NEAR had completed a 13-month heliocentric orbit with the intention of rendezvousing with Eros. Beginning on January 24, 2001, the spacecraft conducted approaches to Eros's surface, coming as close as 5 km away, in preparation for a safe landing. On February 12, 2001, NEAR descended to Eros's surface, surprising astronomers by safely landing. Following the extension of its high-gain antenna, NEAR's gamma-ray spectrometer was reprogrammed to analyze the composition of Eros's surface. NEAR transmitted its final signals from Eros at 7 p.m. EST on February 28, 2001.[26][27]

Deep Space 1

edit

On July 29, 1999, the Deep Space 1 spacecraft encountered 9969 Braille en route to 19P/Borrelly. At the time of the encounter, Deep Space 1's ultraviolet spectrometer had malfunctioned, but it managed to capture two CCD images during the flyby. Despite a planned close approach of 26 km (16 mi) from Braille,[28] the images were actually taken from an estimated distance of 14,000 km (8,700 mi) due to tracking system issues. This encounter primarily served as a test of Deep Space 1's technology before its subsequent flyby of 19P/Borrelly.[29][30]

2000s

edit

Cassini-Huygens

edit

On January 23, 2000, the Cassini–Huygens spacecraft inadvertently passed within 1,500,000 km (930,000 mi) of asteroid 2685 Masursky while en route to Saturn. Cassini estimated the asteroid's diameter to be just under 15-20 kilometers based on an angular diameter of 0.81–1.08 arcseconds observed hours before its closest approach. However, due to Cassini's distance from Masursky, the spacecraft did not gather vital information about the asteroid.[31]

Stardust

edit

On November 2, 2002, the Stardust spacecraft flew by 5535 Annefrank at a distance of 3,079 km (1,913 mi), en route to sample the coma of 81P/Wild and solar wind. Stardust discovered that Annefrank's size was double the previously estimated diameter and that it had a shape resembling a triangular prism. Additionally, Stardust found that Annefrank was heavily cratered. Debate ensued over whether Annefrank was a contact binary after scrutiny of the images captured by Stardust.[32]

Hayabusa

edit
 
Image of Itokawa from Hayabusa

On September 15, 2005, JAXA’s Hayabusa, Japanese for peregrine falcon, spacecraft took a low-resolution colorized image of its target, 25143 Itokawa.[33] By October 4 of the same year, Hayabusa had reached its Home Position, 7 km (4.3 mi) away from Itokawa.[34] On November 12, Hayabusa deployed its MINERVA probes to analyze Itokawa's surface. However, due to an error during deployment while Hayabusa was moving away from Itokawa, the MINERVA probe reached escape velocity and drifted into heliocentric orbit.[35] On November 19, Hayabusa landed on Itokawa’s surface, but issues arose when its high-gain antenna couldn't be used during the final stage of sampling. Additionally, a power outage caused complications during the handover of the ground station antenna from the Deep Space Network (DSN) to the Usuda Station. Consequently, it was proposed that Hayabusa hovered 10 meters above Itokawa’s surface for 30 minutes before retreating due to a command from ground control. By the time communications were reestablished, Hayabusa was 100 km (62 mi) away from Itokawa and entered safe mode to stabilize attitude control.[36][37] After analyzing the reestablished communication data, JAXA announced on November 23 that Hayabusa had indeed landed on Itokawa's surface.[38]

On November 25, JAXA initiated another attempt to land on Itokawa’s surface. It was proposed that the samplers were activated,[39] but subsequent analysis revealed another issue that prevented sampling.[40] After another communication reestablishment, the probe was put into safe mode.[41] On November 27, Hayabusa experienced a power outage, likely due to a fuel leakage. Three days later, JAXA announced that communication with Hayabusa had been reestablished, although issues with the probe's reaction control system remained. Mission control worked to fix the issue before Hayabusa’s launch window back to Earth.[42] On December 2, an attitude correction was initiated, but the thrusters failed to generate sufficient force. On December 3, it was found that the probe's Z-axis was 20 to 30 degrees from the Sun direction and increasing. As an emergency measure on December 4, xenon propellant from the ion engines was used to correct the spacecraft's spin, and the maneuver was successful. By December 5, attitude control was corrected, reestablishing communication with Hayabusa through its medium gain antenna, which allowed mission control to confirm that the probe's samplers had not been penetrated and still contained samples. On December 6, Hayabusa was 500 km (310 mi) away from Itokawa, and by December 8, an orientation change was observed, leading to the loss of communication.[43][44]

Video of Hayabusa reentering the atmosphere, filmed onboard a camera on NASA's DC-8 Airborne Laboratory.

On March 7, 2006, Hayabusa reconnected with the DSN. The spacecraft was ahead of Itokawa by a mere 13,000 km (8,100 mi), traveling at 3 m (0.0019 mi) per second.[45][46] On March 5, 2010, it was announced that Hayabusa had passed lunar orbit.[47][48] By March 27, Hayabusa was on a trajectory to pass within 20,000 km (12,000 mi) of Earth.[49] On June 13, the reentry capsule was launched, containing minerals and tholins from Itokawa.

On June 13, 2010, at 13:51 UTC, the reentry capsule and Hayabusa entered Earth’s atmosphere.[50] The capsule, weighing 510 kilograms (1,120 lb), landed in the Woomera Prohibited Area in Southern Australia and was recovered at 07:08 UTC (16:38 local) on June 14, 2010.[51][52]

Rosetta

edit
 
Šteins from 800 km (500 mi). Taken aboard Rosetta's OSIRIS camera.

On September 5, 2008, the Rosetta spacecraft flew by 2867 Šteins from a distance of 800 km (500 mi) at a speed of 8.6 km/s en route to 67P/Churyumov–Gerasimenko, limiting the encounter's duration to only a 7-minute flyby. However, 15 scientific instruments aboard the Rosetta spacecraft obtained vital informational data about Šteins in this short period.[53] The flyby occurred while Šteins was illuminated by the sun from the spacecraft's perspective, resulting in clearer images. However, due to the rapid flyby, the images taken were blurred.[54]

References

edit
  1. ^ "Chapter 14: Launch". science.nasa.gov. Retrieved 30 May 2024.
  2. ^ "Space Power Chapter 7: Electric Rockets – Opening the Solar System – NSS". Retrieved 2024-04-28.
  3. ^ "Chapter 13: Navigation". science.nasa.gov. Retrieved 30 May 2024.
  4. ^ "How does a spacecraft change course?". qrg.northwestern.edu. Retrieved 30 May 2024.
  5. ^ Chan, Queenie Hoi Shan; Stroud, Rhonda; Martins, Zita; Yabuta, Hikaru (12 May 2020). "Concerns of Organic Contamination for Sample Return Space Missions". Space Science Reviews. 216 (4): 56. Bibcode:2020SSRv..216...56C. doi:10.1007/s11214-020-00678-7. PMC 7319412. PMID 32624626.
  6. ^ "Star Camera". NASA. May 2004. Archived from the original on July 21, 2011. Retrieved 25 May 2012.
  7. ^ "Basics of Spaceflight: Units of Measure". science.nasa.gov. Retrieved 30 May 2024.
  8. ^ "Spacecraft On-Board Computer (OBC)". Honeywell Aerospace Technologies. Retrieved 30 May 2024.
  9. ^ Schauer, Katherine (6 October 2020). "Space Communications: 7 Things You Need to Know". NASA.gov. Retrieved 30 May 2024.
  10. ^ "Calculating Solar Power in Space". Jet Propulsion Laboratory. Retrieved 30 May 2024.
  11. ^ "Radioisotope Thermoelectric Generator". science.nasa.gov. Retrieved 30 May 2024.
  12. ^ Uri, John (3 December 2018). "45 Years Ago, Pioneer 10 First to Explore Jupiter". NASA.gov. Retrieved 30 May 2024.
  13. ^ "Solar System Exploration - Galileo". NASA. Archived from the original on 26 June 2013. Retrieved 21 April 2013.
  14. ^ Veverka, J.; Belton, M.; Klaasen, K.; Chapman, C. (1994). "Galileo's Encounter with 951 Gaspra: Overview". Icarus. 107 (1): 2–17. Bibcode:1994Icar..107....2V. doi:10.1006/icar.1994.1002.
  15. ^ P. C. Thomas; J. Veverka; D. Simonelli; P. Helfenstein; et al. (1994). "The Shape of Gaspra". Icarus. 107 (1): 23–36. Bibcode:1994Icar..107...23T. doi:10.1006/icar.1994.1004.
  16. ^ J.C. Granahan; F.P. Fanale & M.S. Robinson (1994). "A Galileo Multi Spectral Instrument Analysis of 951 Gaspra" (PDF). Abstracts of the 25th Lunar and Planetary Science Conference, Held in Houston, TX, 14–18 March 1994: 453.
  17. ^ Stooke, P. J. (1996). "The Surface of 951 Gaspra". Earth, Moon, and Planets. 75 (1): 53–75. Bibcode:1996EM&P...75...53S. doi:10.1007/BF00056288. S2CID 122026431.
  18. ^ Chapman, Clark R. (October 1996). "S-Type Asteroids, Ordinary Chondrites, and Space Weathering: The Evidence from Galileo's Fly-bys of Gaspra and Ida". Meteoritics. 31 (6): 699–725. Bibcode:1996M&PS...31..699C. doi:10.1111/j.1945-5100.1996.tb02107.x.
  19. ^ Holm, Jeanne (June 1994). Jones, Jan (ed.). "Discovery of Ida's Moon Indicates Possible "Families" of Asteroids". The Galileo Messenger (34). Archived from the original on 24 June 2010. Retrieved 2008-10-23. Alt URL
  20. ^ "Asteroid Ida and Its Moon". Jet Propulsion Laboratory. 1 February 1996. Retrieved 31 May 2024.
  21. ^ J. Veverka; et al. (1999). "NEAR Encounter with Asteroid 253 Mathilde: Overview". Icarus. 140 (1): 3–16. Bibcode:1999Icar..140....3V. doi:10.1006/icar.1999.6120.
  22. ^ Kelley, M. S.; Gaffey, M. J.; Reddy, V. (March 12–16, 2007). "Near-IR Spectroscopy and Possible Meteorite Analogs for Asteroid (253)". 38th Lunar and Planetary Science Conference. League City, Texas: Lunar & Planetary Institute. p. 2366. Bibcode:2007LPI....38.2366K.
  23. ^ "Solar System Exploration - NEAR Shoemaker". NASA. Archived from the original on 26 June 2013. Retrieved 21 April 2013.
  24. ^ "The NEAR Rendezvous Burn Anomaly of December 1998" (PDF). Final Report of the NEAR Anomaly Review Board. November 1999. Archived (PDF) from the original on 2022-10-09. Retrieved February 2, 2017.
  25. ^ "NEAR Shoemaker". NASA Space Science Data Coordinated Archive. Retrieved February 5, 2019.
  26. ^ Siddiqi, Asif A. (2018). Beyond Earth: A Chronicle of Deep Space Exploration, 1958–2016 (PDF). The NASA history series (second ed.). Washington, DC: NASA History Program Office. p. 2. ISBN 9781626830424. LCCN 2017059404. SP2018-4041. Archived (PDF) from the original on 2022-10-09.
  27. ^ "'NEAR Shoemaker's Silent Treatment". Applied Physics Laboratory. February 23, 2001.
  28. ^ "A CLOSE-UP OF AN ASTEROID". National Aeronautics and Space Administration. Archived from the original on March 20, 2009.
  29. ^ Lazzarin, M.; Fornasier, S.; Barucci, M. A.; Birlan, M. (August 2001). "Groundbased investigation of asteroid 9969 Braille, target of the spacecraft mission Deep Space 1" (PDF). Astronomy and Astrophysics. 375: 281–284. Bibcode:2001A&A...375..281L. doi:10.1051/0004-6361:20010789. Retrieved 22 June 2017.
  30. ^ Oberst, J.; Mottola, S.; Di Martino, M.; Hicks, M.; Buratti, B.; Soderblom, L.; et al. (September 2001). "A Model for Rotation and Shape of Asteroid 9969 Braille from Ground-Based Observations and Images Obtained during the Deep Space 1 (DS1) Flyby". Icarus. 153 (1): 16–23. Bibcode:2001Icar..153...16O. doi:10.1006/icar.2001.6648. Retrieved 22 June 2017.
  31. ^ "PIA02449: Masursky". NASA/JPL – Photojournal. 11 February 2000. Retrieved 7 April 2018.
  32. ^ Duxbury, Thomas C.; Newburn, Ray L.; Acton, Charles H.; Carranza, Eric; McElrath, Timothy P.; Ryan, Robert E.; et al. (February 2004). "Asteroid 5535 Annefrank size, shape, and orientation: Stardust first results" (PDF). Journal of Geophysical Research. 109 (E2): E02002. Bibcode:2004JGRE..109.2002D. doi:10.1029/2003JE002108. Retrieved 22 June 2017.
  33. ^ Japan Aerospace Exploration Agency (14 September 2005). "The synthesized pseudo-color image of Itokawa which took by Hayabusa / Topics". ISAS. Retrieved 14 June 2010.
  34. ^ Japan Aerospace Exploration Agency (4 October 2005). "Hayabusa arrives at Home Position, and Current Status of Hayabusa Spacecraft / Topics". ISAS. Retrieved 14 June 2010.
  35. ^ "Hayabusa Does Not Land on Asteroid in First Attempt, But Successfully Delivers Target Marker – Planetary News | The Planetary Society". Planetary.org. Archived from the original on 21 June 2011. Retrieved 14 June 2010.
  36. ^ "Hayabusa Does Not Land on Asteroid in First Attempt, But Successfully Delivers Target Marker – Planetary News | The Planetary Society". Planetary.org. Archived from the original on 21 June 2011. Retrieved 14 June 2010.
  37. ^ 2005.11.20 in Hayabusa (20 November 2005). "Fate of Hayabusa: 5thstar_管理人_日記". 5thstar.air-nifty.com. Retrieved 14 June 2010.{{cite web}}: CS1 maint: numeric names: authors list (link)
  38. ^ Japan Aerospace Exploration Agency. "Hayabusa Landed on and Took Off from Itokawa successfully – Detailed Analysis Revealed / Topics". ISAS. Retrieved 14 June 2010.
  39. ^ "Japan probe 'almost certainly' collected first-ever asteroid samples". Spacedaily.com. 26 November 2005. Retrieved 14 June 2010.
  40. ^ "Space news and outer space articles from New Scientist – New Scientist Space – New Scientist". New Scientist Space. Archived from the original on 18 April 2009. Retrieved 14 June 2010.
  41. ^ in はやぶさリンク. "[HAYABUSA link] The press conference at 16:00 JST 26th: 松浦晋也のL/D". Smatsu.air-nifty.com. Retrieved 14 June 2010.
  42. ^ "Hayabusa: Team Re-Establishes Command and Works to Bring its Falcon Home – Planetary News | The Planetary Society". Planetary.org. Archived from the original on 30 April 2010. Retrieved 14 June 2010.
  43. ^ 宇宙航空研究開発機構(JAXA)宇宙科学研究所. "「はやぶさ」探査機の状況について / トピックス". ISAS. Retrieved 14 June 2010.
  44. ^ in はやぶさリンク. "[HAYABUSA link]: Press Conference at 16:50 on 7th Dec. JST: 松浦晋也のL/D". Smatsu.air-nifty.com. Retrieved 14 June 2010.
  45. ^ Japan Aerospace Exploration Agency. "Current Status of Hayabusa Spacecraft – Communication and Operation Resumption / Topics". ISAS. Retrieved 14 June 2010.
  46. ^ in はやぶさリンク. "本日午後7時からの記者会見: 松浦晋也のL/D". Smatsu.air-nifty.com. Retrieved 14 June 2010.
  47. ^ 小惑星探査機「はやぶさ」 (in Japanese). 10 March 2010. Archived from the original on 16 March 2010. Retrieved 12 March 2010.
  48. ^ 軌道情報 (in Japanese). 5 March 2010. Archived from the original on 16 June 2011. Retrieved 26 March 2010.
  49. ^ 小惑星探査機「はやぶさ」搭載イオンエンジンの連続運転による軌道制御の終了について (in Japanese). JAXA. 27 March 2010. Retrieved 27 March 2010.
  50. ^ Mission Accomplished For Japan's Asteroid Explorer Hayabusa Archived 16 June 2010 at the Wayback Machine
  51. ^ Ryall, Julian (11 June 2009). "Asteroid Probe Set to "Collide" With Earth". National Geographic. Archived from the original on 14 June 2009. Retrieved 12 June 2010.
  52. ^ "Retrieving the Capsule completed". JAXA. Retrieved 14 June 2010.
  53. ^ "Encounter of a different kind: Rosetta observes asteroid at close quarters". ESA Rosetta News. Archived from the original on 10 May 2009. Retrieved 29 May 2009.
  54. ^ Talevi, Monica (4 September 2008). "Rosetta Steins fly-by timeline". European Space Agency. Retrieved 5 September 2008.[permanent dead link]