Up to now two spacecraft have been launched for an asteroid sample return mission. The first one Hayabusa is a completed mission and now OSIRIS-REx is an ongoing mission. Hayabusa was launched in 2003, many years before OSIRIS-REx. Technology now is much more better. What are the improvements in capabilities for the current asteroid sample return mission? What are the technological differences?

Hayabusa spacecraft, JAXA Hayabusa spacecraft, JAXA.

OSIRIS-REx spacecraft, NASA OSIRIS-REx spacecraft, NASA.

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    $\begingroup$ The question is easy to ask, but broad. What can you not find in external sources that you want additional help with? Note that jvriesem took the information in his answer mostly from Wikipedia. You could have found that easily. $\endgroup$ – user10509 Sep 21 '16 at 7:25
  • $\begingroup$ @JanDoggen spacecrafts and missions could be similar, but the techniques used in these missions, technology and engineering instruments used may be different. For example two spacecraft could use both ion propulsion energy, but what engines are used how much power or for how long could give thrust ect. Not even only the propulsive part but also for other instruments, engeniering parts that will be used for different purposes, what new technology do they use, how are they constructed. $\endgroup$ – Mark777 Sep 21 '16 at 15:26
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    $\begingroup$ @JanDoggen Or for instruments for the same purpose what improvements are done. I have written in my comment at jvriesem answer, that I am interested for technological part. A comparison not just for what will they do, but what instruments will they use with what improvement or advantage. Since for the moment this is the info that could be found, even if I have read that info before i should accept that answer, because this is all we can get for now. If you can answer my question by including details than your answer will be accepted as the right answer :). $\endgroup$ – Mark777 Sep 21 '16 at 15:55
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    $\begingroup$ I'm voting to reopen because 1) the excellent answer demonstrates that the question was not too broad nor too unfocussed to be answered here, and 2) there's no reason to deny future readers an opportunity to post additional answers to supplement it. $\endgroup$ – uhoh Jun 6 at 10:55
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    $\begingroup$ +1 Supporting re-opening. This is a good question. $\endgroup$ – Anton Hengst Jun 6 at 14:49

Here's a quick comparison of the two missions. Differences to follow.


  • Name: Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer
  • Lead Institution(s): NASA (USA), University of Arizona
  • Principle Investigator (PI): Dante Lauretta (University of Arizona)
  • Target: 101955 Bennu
  • Launch date: 8 September 2016
  • Return date: 24 September 2024 (anticipated)
  • Sample mass: 60 grams - 2 kg (anticipated)
  • Science objectives:
    • Return and analyze a sample of pristine carbonaceous asteroid regolith in an amount sufficient to study the nature, history, and distribution of its constituent minerals and organic material.
    • Map the global properties, chemistry, and mineralogy of a primitive carbonaceous asteroid to characterize its geologic and dynamic history and provide context for the returned samples.
    • Document the texture, morphology, geochemistry, and spectral properties of the regolith at the sampling site in situ at scales down to millimeters.
    • Measure the Yarkovsky effect (a thermal force on the object) on a potentially hazardous asteroid and constrain the asteroid properties that contribute to this effect.
    • Characterize the integrated global properties of a primitive carbonaceous asteroid to allow for direct comparison with ground-based telescopic data of the entire asteroid population.


  • Name: はやぶさ (literally, "Peregrine Falcon") (source)
  • Lead Institution(s): JAXA (Japan)
  • Principle Investigator (PI): Junichiro Kawaguchi (Institute of Space and Astronautical Science)
  • Target: 25143 Itokawa
  • Launch date: 9 May 2003
  • Sampling date: November 2005
  • Return date: 13 June 2010 (recovered June 14, 2010)
  • Sample mass: < 1 gram
  • Science objectives: (my brief summary of the info from this page)
    • Determine and map surface morphology, composition, etc. -- in many ways
    • Search for possible asteroid satellites and dust rings
    • Reveal history of impacts from other asteroid and comet fragments
    • Provide accurate shape and mass determinations
    • Establish relationship between 25143 Itokawa and meteorite types (composition, type, history, etc.)


Besides the administration of each project (USA vs. Japan), and the spacecraft themselves, the two missions are fairly similar. There are some notable differences, however, and for the sake of the OP, I'll focus on these.

Due to some failures, most of the spacecraft burned up upon re-entry. The Hayabusa mission returned less than a gram of material. According to Dante Lauretta (PI of OSIRIS-REx) in this publication, the OSIRIS-REx mission is in part an attempt to continue the work of Hayabusa, as OSIRIS-REx was hugely influenced by Hayabusa.

In the same publication, Lauretta points out that Hayabusa's difficulties were due mainly to limited knowledge of Itokawa and insufficient simulation of the sampling process ahead of time. OSIRIS-REx will spend almost a year characterizing Bennu while orbiting it, however, so scientists on Earth will have a better understanding of the asteroid and (importantly) its surface before actually sampling it. Whereas Hayabusa actually landed on Itokawa for about 30 minutes, OSIRIS-REx will touch it only briefly.

Although both Bennu and Itokawa are of similar size (~400-500 m in diameter), a key difference is that Bennu is a near Earth asteroid, meaning that it could collide with Earth, and Itokawa is not. Also, the shape of Itokawa is more like a slightly bent potato, whereas Bennu is much more rounded.

Itokawa Image of Itokawa

Bennu Artist's rendering of Bennu

As for technology, Hayabusa used an explosive harpoon to kick up particles into its collection module. OSIRIS-REx will essentially cover the sample site with an inverted pan-like contraption and release several bursts of nitrogen gas at the regolith to kick up particles into its collection module.

Since OSIRIS-REx will spend a year orbiting Bennu, it is equipped with a suite of telescopes/imagers, radar, spectroscopes and gravitometers to keep it busy during this time. Many of these instruments allow collaborative, independent analyses of the inferences made by the other instruments on board. While Hayabusa also had several similar instruments, it did not have as many as OSIRIS-REx.

You can read about the individual instruments on the official pages for Hayabusa (also here) and OSIRIS-REx (also here). These pages, and links therein, can provide you with a wealth of instrumentation and engineering details.

Sources used

Except where noted, information was taken from Wikipedia's pages on Hayabusa and OSIRIS-REx. Some information was also based on discussions with colleagues involved with OSIRIS-REx.

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  • $\begingroup$ It is probably also worthwhile to mention that Lockheed Martin was the manufacturer of OSIRIS-REx and NEC assisted in the development of Hayabusa. $\endgroup$ – called2voyage Sep 20 '16 at 19:53
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    $\begingroup$ A near-Earth asteroid is not necessarily at any risk of hitting Earth. Some never cross Earth's orbit, some have orbits with periods or inclinations that never bring them close enough in the foreseeable future. Bennu is classified as a PHA, meaning its projected trajectory does come close enough that there is a very minimal possibility it could hit us, but both it and Itokawa cross Earth's orbit and are the same class of NEA, Apollos. $\endgroup$ – kim holder Sep 20 '16 at 20:22
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    $\begingroup$ Also, Hayabusa also assisted in the study of the Yarkovsky effect. $\endgroup$ – called2voyage Sep 20 '16 at 20:53
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    $\begingroup$ @jvriesem impressive work, you have made a comparison between this spacecrafts in all directions. I was interested mostly for the technological part, but much more info is much more helpful. I congratulate and thank you for all your research. $\endgroup$ – Mark777 Sep 20 '16 at 23:57
  • $\begingroup$ @Mark777: Thank you for asking! It was fun learning about this. I still feel like I didn't fully answer it (I said more about the differences between the missions than about their technology), but that's as far as I'll go. :-) $\endgroup$ – jvriesem Sep 23 '16 at 22:18

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