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Project Lyra: sending spacecraft to chase Oumuamua using Sun for Oberth maneuver

17 points by blindriver 3y ago

ano-ther 3y ago
Cool. Or rather hot, as it seems to come pretty close to the sun. Here is more about the project: https://en.m.wikipedia.org/wiki/Project_Lyra https://en.m.wikipedia.org/wiki/Project_Lyra And TIL about the Oberth effect: https://en.m.wikipedia.org/wiki/Oberth_effect https://en.m.wikipedia.org/wiki/Oberth_effect
Valgrim 3y ago
If those objects happen to be more frequent than expected, I think we should envision a way to send small probes with the ability to slowly mine their resources and build things like larger communication antennas or telescope mirrors using in-situ materials, taking advantage of their great mass and speed to create much bigger structures than we could reasonably send out there
HappySweeney 3y ago
A back-of-napkin calculation says this maneuver can also be used to send a probe to Proxima Centauri in ... 128 days? Why are we not doing that?
- LASR 3y ago
  Not sure if you’re sarcastic or not but Promixa is 4+ light years away. So unless we have FTL tech, this is impossible.
  - HappySweeney 3y ago
    Nope, just bad at both math and basic reasoning yesterday.
eggy 3y ago
But Oumuamua will engage it's cloaking device or warp speed. After all it's an alien ship that will be divulged in the latest round IAP disclosures by the US government ;)
mitsu_at 3y ago
This looks like scenario B from this paper: https://arxiv.org/pdf/1902.04935.pdf https://arxiv.org/pdf/1902.04935.pdf Mission E-DSM-E-J-6SR-1I (15.3 km/s of delta v required): (2030-06-09) Launch from Earth (2031-11-05) Deep Space Maneuver at 3.2 AU (2033-04-17) Earth return (2034-07-12) Jupiter arrival (2036-02-24) 6 solar radii (2052-07-29) 'Oumuamua arrival A Solar Oberth mission requires a heat shield, which takes up weight that can be used for other payload. It's also riskier. There are also proposals for other mission profiles that only use the Jupiter Oberth, but these would either require more delta v or more inner planet assists, and so could take longer. Example: https://arxiv.org/pdf/2201.04240.pdf https://arxiv.org/pdf/2201.04240.pdf Mission V-E-DSM-E-J with 2028 launch date, 26 years flight duration, 15.8 km/s of delta v required. Animation: https://www.youtube.com/watch?v=qrCUsAGZjUw https://www.youtube.com/watch?v=qrCUsAGZjUw Note that delta v does not necessarily imply anything about the final spacecraft velocity. Rather, it's indicative how much thrust you need throughout the mission. So how much delta v you have at your disposal is a function of what kind of rocket(s) you have and how much propellant you have. And how far you can get with a certain delta v budget depends on how smartly you use it. To get the most bang for your buck, you fire your rockets at strategic locations in your orbit. This is where the physics behind Oberth maneuver come in: It's most efficient to gain kinetic energy at periapsis, when you are travelling the fastest. This is because kinetic energy is 1/2 mv^2. The greater kinetic energy will take you farther out of the gravity well than if you fired your engines at a lower velocity.
- jfengel 3y ago
  How fast is it going when it arrives at Oumuamua? Or to put it another way... how long will it have to gather data?
  - mitsu_at 3y ago
    In the two examples above, the Solar Oberth Maneuver would have it pass 1I with a relative speed of ~30 km/s. The Jupiter-only maneuver passes 1I with a relative speed of ~18 km/s.

17 points by blindriver 3y ago

Cool. Or rather hot, as it seems to come pretty close to the sun. Here is more about the project: https://en.m.wikipedia.org/wiki/Project_Lyra https://en.m.wikipedia.org/wiki/Project_Lyra And TIL about the Oberth effect: https://en.m.wikipedia.org/wiki/Oberth_effect https://en.m.wikipedia.org/wiki/Oberth_effect

Valgrim 3y ago

If those objects happen to be more frequent than expected, I think we should envision a way to send small probes with the ability to slowly mine their resources and build things like larger communication antennas or telescope mirrors using in-situ materials, taking advantage of their great mass and speed to create much bigger structures than we could reasonably send out there

HappySweeney 3y ago

A back-of-napkin calculation says this maneuver can also be used to send a probe to Proxima Centauri in ... 128 days? Why are we not doing that?

LASR 3y ago
Not sure if you’re sarcastic or not but Promixa is 4+ light years away. So unless we have FTL tech, this is impossible.
- HappySweeney 3y ago
  Nope, just bad at both math and basic reasoning yesterday.

eggy 3y ago

But Oumuamua will engage it's cloaking device or warp speed. After all it's an alien ship that will be divulged in the latest round IAP disclosures by the US government ;)

mitsu_at 3y ago

This looks like scenario B from this paper: https://arxiv.org/pdf/1902.04935.pdf https://arxiv.org/pdf/1902.04935.pdf Mission E-DSM-E-J-6SR-1I (15.3 km/s of delta v required): (2030-06-09) Launch from Earth (2031-11-05) Deep Space Maneuver at 3.2 AU (2033-04-17) Earth return (2034-07-12) Jupiter arrival (2036-02-24) 6 solar radii (2052-07-29) 'Oumuamua arrival A Solar Oberth mission requires a heat shield, which takes up weight that can be used for other payload. It's also riskier. There are also proposals for other mission profiles that only use the Jupiter Oberth, but these would either require more delta v or more inner planet assists, and so could take longer. Example: https://arxiv.org/pdf/2201.04240.pdf https://arxiv.org/pdf/2201.04240.pdf Mission V-E-DSM-E-J with 2028 launch date, 26 years flight duration, 15.8 km/s of delta v required. Animation: https://www.youtube.com/watch?v=qrCUsAGZjUw https://www.youtube.com/watch?v=qrCUsAGZjUw Note that delta v does not necessarily imply anything about the final spacecraft velocity. Rather, it's indicative how much thrust you need throughout the mission. So how much delta v you have at your disposal is a function of what kind of rocket(s) you have and how much propellant you have. And how far you can get with a certain delta v budget depends on how smartly you use it. To get the most bang for your buck, you fire your rockets at strategic locations in your orbit. This is where the physics behind Oberth maneuver come in: It's most efficient to gain kinetic energy at periapsis, when you are travelling the fastest. This is because kinetic energy is 1/2 mv^2. The greater kinetic energy will take you farther out of the gravity well than if you fired your engines at a lower velocity.

jfengel 3y ago
How fast is it going when it arrives at Oumuamua? Or to put it another way... how long will it have to gather data?
- mitsu_at 3y ago
  In the two examples above, the Solar Oberth Maneuver would have it pass 1I with a relative speed of ~30 km/s. The Jupiter-only maneuver passes 1I with a relative speed of ~18 km/s.