Cubesats for Solar System Exploration |
Cubesats for Solar System Exploration |
Aug 8 2020, 05:14 PM
Post
#1
|
|
Member Group: Members Posts: 715 Joined: 22-April 05 Member No.: 351 |
[ADMIN NOTE: New topic started using moved posts from Pallas telescopic observation topic. Please read and keep rule 1.9 in mind. Thanks!]
I was hoping that NASA would select the Athena mission to do a flyby of Pallas using a cubesat spacecraft under the SIMPLEx program. It selected the Janus mission to flyby two near Earth asteroid binary systems instead. The Athena team plans to submit again. -------------------- |
|
|
Aug 22 2020, 08:43 PM
Post
#2
|
|
Senior Member Group: Members Posts: 2542 Joined: 13-September 05 Member No.: 497 |
As interesting as the Oberth effect is, it seems to have seen limited use in interplanetary missions so far, largely because spacecraft either don't have significant post-injection delta V capability or they need it all for orbit insertion at the target. (It does get used to the extent possible during that orbit insertion.)
For example, look at where the burns were in the Juno 2+ deltaV-EGA trajectory. https://trs.jpl.nasa.gov/bitstream/handle/2...08-2728_A1b.pdf -------------------- Disclaimer: This post is based on public information only. Any opinions are my own.
|
|
|
Aug 22 2020, 10:19 PM
Post
#3
|
|
Member Group: Members Posts: 684 Joined: 24-July 15 Member No.: 7619 |
As interesting as the Oberth effect is, it seems to have seen limited use in interplanetary missions so far, largely because spacecraft either don't have significant post-injection delta V capability or they need it all for orbit insertion at the target. (It does get used to the extent possible during that orbit insertion.) For example, look at where the burns were in the Juno 2+ deltaV-EGA trajectory. https://trs.jpl.nasa.gov/bitstream/handle/2...08-2728_A1b.pdf You are absolutely right. My fault. Until I read the story of Hiten/Delbruno https://press.princeton.edu/books/hardcover...stial-mechanics and watched Virginia Tech's Department of Aerospace and Ocean Engineering - Ross Dynamics Lab https://youtu.be/fV0kUmtQWZU?t=586 I didn't realized that this is OBVIOUS to me because it is logically identical to chemistry principles of "activation energy" and "phase space." And these have NO analog in orbital mechanics. So here goes- 1) Launch a rack with cubesats into LEO. 2) Launch a fully fueled booster rocket into LEO. 3) Do a half-century ago Gemini program dock of cubesat payload & fully fueled booster. 4) Use a "Hiten-DelBruno maneuver" to move cubesats & booster from an Earth-Moon Lagrange point to a Sun-Earth Lagrange point. 6) Light the booster rocket and send a payload of cubesats to Mars & the asteroid belt using 10% of the fuel you'd usually need. |
|
|
Aug 22 2020, 11:39 PM
Post
#4
|
|
Senior Member Group: Members Posts: 2542 Joined: 13-September 05 Member No.: 497 |
1) Launch a rack with cubesats into LEO. 2) Launch a fully fueled booster rocket into LEO. 3) Do a half-century ago Gemini program dock of cubesat payload & fully fueled booster. 4) Use a "Hiten-DelBruno maneuver" to move cubesats & booster from an Earth-Moon Lagrange point to a Sun-Earth Lagrange point. 6) Light the booster rocket and send a payload of cubesats to Mars & the asteroid belt using 10% of the fuel you'd usually need. Did it turn out that step 5 was unneeded? Would this work in theory? Probably. Is it practical from an engineering perspective? Not really, at least not right now. For example, there are no "space tugs" with high delta V and long on-orbit duration. The Centaur upper stage, for example, has a lifetime measured in hours or maybe a few days. There are a lot of competing constraints in mission design, it's not all about orbital dynamics. -------------------- Disclaimer: This post is based on public information only. Any opinions are my own.
|
|
|
Aug 23 2020, 01:19 AM
Post
#5
|
|
Member Group: Members Posts: 684 Joined: 24-July 15 Member No.: 7619 |
The Centaur upper stage, for example, has a lifetime measured in hours or maybe a few days. Do you think it could be adapted to last 4 months? That would allow a Hiten-style path and put an upper stage into lunar orbit that arrives 90% full. I looked but could not find Centaur on orbit specifications; can you post the link to those refernces? (That is why I went with the Atlas Heavy RP1-LOX "double stack," it appears the RP1 lasts longer than cryogenic H2. However I'm guessing that MethaLox is stable for at least as long, given that SpaceX starship reliance on MethaLox at Mars. Do the pros/mods have a list of the rocket fuels at used t Mars? I would guess that somebody here knows the history of Mars mission rocket fuels? I ask because that IS part of the basic blueprint for cubesat fuel to Mars and the asteroid belt. (If not, sounds like a great conference poster!) |
|
|
Aug 23 2020, 01:38 AM
Post
#6
|
|
Senior Member Group: Members Posts: 2542 Joined: 13-September 05 Member No.: 497 |
Do the pros/mods have any list of the various rocket fuels used on the way to Mars? All US Mars missions have used either hydrazine monopropellant or MMH/N2O4 bipropellant. I'm unaware of any deep-space application for any cryogenic fuel of any kind after initial injection by the launch vehicle. Centaur duration: "The present day Centaur vehicle looses [sic] upwards of 17-20 % lbm of Hydrogen per day" https://www.ulalaunch.com/docs/default-sour...n-2006-7270.pdf (There are also avionics thermal control constraints but I'm not sure how driving those are.) Keep in mind that any mission of reasonable cost pretty much has to use off-the-shelf systems; they typically can't afford to develop their own from-scratch flight infrastructure. -------------------- Disclaimer: This post is based on public information only. Any opinions are my own.
|
|
|
Lo-Fi Version | Time is now: 24th September 2024 - 11:52 AM |
RULES AND GUIDELINES Please read the Forum Rules and Guidelines before posting. IMAGE COPYRIGHT |
OPINIONS AND MODERATION Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators. |
SUPPORT THE FORUM Unmannedspaceflight.com is funded by the Planetary Society. Please consider supporting our work and many other projects by donating to the Society or becoming a member. |