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Arrow TESS
by OrbitHangar 04-01-2018, 12:49 PM


Author: brianj

The Transiting Exoplanet Survey Satellite (TESS) spacecraft and launch scenario for 18 April 2018 (1st stage flyback to ASDS).

Installation and operation notes in /Doc/TESS

 

REQUIRED ADD-ON

"Falcon9 for Orbiter2016"
https://www.orbithangar.com/searchid.php?ID=7091



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Old 04-01-2018, 12:55 PM   #2
Kyle
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Thank you, Brian!
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Old 04-01-2018, 01:36 PM   #3
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Thanks Brian!
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Old 04-01-2018, 03:33 PM   #4
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My pleasure, hope it's useful :-)
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Old 04-16-2018, 05:15 PM   #5
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SpaceX TESS launch press kit is online:
http://www.spacex.com/sites/spacex/f...sspresskit.pdf

No mention of any 1st stage "boostback" burn - so Entry and Descent burns only?

If that is the case, I guess the parking orbit will be more like 200km x 600km (if they really are targeting a 600km PeA at final orbit insertion).

Fairing(s) will have parafoil but no attempt to actually catch them this time, apparently.

Good luck TESS and SpaceX teams
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Old 04-16-2018, 05:47 PM   #6
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The current location of the drone ship would tell whether they are planning doing a boostback or not? Perhaps some maritime warning site will disclose that info.

Check Musk's Twitter. It looks like they will try something new. Recovering the upper stage with a giant party balloon? Sounds like fun.
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Old 04-16-2018, 08:21 PM   #7
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Quote:
Originally Posted by Marijn View Post
 The current location of the drone ship would tell whether they are planning doing a boostback or not? Perhaps some maritime warning site will disclose that info.
From Reddit, ASDS location West 77.506 North 28.874, final orbit insertion 200km x 275,000km.

That would suggest parking orbit of 200km x 200km at 29.5deg inc.
The ASDS seems a bit close for an EDL-Only burn profile, but who knows. Will find out soon, hopefully :-)

The Falcon9 add-on needs a fuel-reserve of ~70000kg to put the 1st stage near the ASDS, but then it's way too heavy on the way down.
Maybe it'll work better if I offload some fuel first. Or change 1st stage ApA.

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Originally Posted by Marijn View Post
 Check Musk's Twitter. It looks like they will try something new. Recovering the upper stage with a giant party balloon? Sounds like fun.
Not sure what he's on about there. Inflatable heatshield for 2nd stage? Haven't heard anything about it with regard to this launch, certainly.

Cheers,
BrianJ
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Old 04-16-2018, 09:14 PM   #8
Marijn
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Quote:
Originally Posted by BrianJ View Post
 Not sure what he's on about there.
'And then land on a bouncy house'. Something very interesting is coming up it seems. Something somehow was not picked up by any media. I really enjoy how details gradually become available. It must be hard to keep up with this as an add-on developer
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Old 04-16-2018, 10:27 PM   #9
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Gonna have to update the launch date...

Also, has anyone pulled-off TESS's super-interesting trajectory?

Last edited by boogabooga; 04-16-2018 at 10:30 PM.
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Old 04-16-2018, 10:48 PM   #10
Marijn
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Aww. I was just ready for it. What's the problem? Weather?
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Old 04-17-2018, 04:30 AM   #11
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Quote:
Originally Posted by Marijn View Post
 Aww. I was just ready for it. What's the problem? Weather?
Nothing known. Last tweet by SpaceX was:

Quote:
Standing down today to conduct additional GNC analysis, and teams are now working towards a targeted launch of @NASA_TESS on Wednesday, April 18.
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Old 04-17-2018, 06:09 PM   #12
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Originally Posted by boogabooga View Post
 Gonna have to update the launch date...
v.180417 updated on OH with new launch scenario.
Now uses reported ASDS position, 200km parking orbit, 29.5deg.inc., 1st stage Flyback-EDL to ASDS.

The ASDS is less than 1/2 the usual distance from LC-40, for 1st stage EDL-Only burn profile. Can't see how they can do it unless they offload >50mt propellant. I'm betting there is a Boostback burn.

Quote:
Originally Posted by boogabooga View Post
 Also, has anyone pulled-off TESS's super-interesting trajectory?
Yep, targeted a 40deg.inc.(ecliptic) Earth orbit at 17 x 59 earth-radii, thats ~ 108000km x 375000km
That didn't look too stable on a 1yr plot(LagrangeMFD) so I pushed the ApA back out to 440000km and it looks pretty solid.
Orbit period/lunar resonance is the important thing, I think.
I must have hit the Moon a bit fast, needed to do a hefty retrograde burn at 1st Perigee after flyby to pull the ApA down. Still had >240m/s dV remaining.

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Originally Posted by Marijn View Post
 It must be hard to keep up with this as an add-on developer
SpaceX trying out every idea they can come up with, simply for the fun of it I think. We await the "party balloon and bouncy castle" trick.

Last edited by BrianJ; 04-17-2018 at 06:25 PM.
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Old 04-18-2018, 06:31 PM   #13
Marijn
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Quote:
Originally Posted by BrianJ View Post
 v.180417 updated on OH with new launch scenario.
Now uses reported ASDS position, 200km parking orbit, 29.5deg.inc., 1st stage Flyback-EDL to ASDS.
Thanks again for the quick updates. I am having lots of fun with it. All systems and weather are go at the moment, so hopefully we'll see in a few hours how they do it and what surprises are in store. My guess is that they will test some kind of ballute to slow the upper stage down.

Wy did you choose 29.5 deg inc.? Because of the reported ASDS position? Otherwise I would expect 28.6 degrees inc. like the base latitude to be optimal.

And do you know what inc. the final orbit has after the lunar gravity assist? I think I read 37 degrees somewhere, but I am unsure if that's correct and what reference plane is used. Since TESS remains a satellite of earth, it makes sense to me that the equatorial plane is ment.

---------- Post added at 08:31 PM ---------- Previous post was at 08:17 PM ----------

Quote:
Originally Posted by BrianJ View Post
 We await the "party balloon and bouncy castle" trick.
I am trying to make some sense of what Musk said on Twitter. My thoughts at the moment: It's gonna be a big ballute, some sort of an inflatable cone which extends from the back which will create drag and slow it down. When it has slowed down, a parachute will deploy from the other side. It will splashdown with the ballute on the bottom side. That's the bouncing castle. And the upper-stage falls into the ballute to keep it dry.
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Old 04-18-2018, 09:59 PM   #14
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@Marijn
Hi,
yep, hope all goes well for tonight's launch attempt.
I'm doubtful they will be trying anything new on the 2nd stage this time - I think they'll make a small burn after payload separation and send it heliocentric. But who knows - it'll be going super-fast(not far off lunar return velocity) if it returns to Earth, so maybe a good time to test stuff? We'll see soon :-)

29.5deg.inc. due to ASDS position, and also it works fine for TLI for lunar intercept in ~26days. As you say, 28.6deg.inc. is optimal dV-wise, but lots of other constraints on launch time/azimuth/inc. so a few degrees isn't much to worry about.

TESS final orbit at 37deg.inc. sounds right (from the press conference?) but I don't think they mentioned reference frame, so we have to guess. I assumed ecliptic, but maybe I'm wrong. Also mentioned was the 17 x 59 Earth-radii orbit perigee/apogee - but how accurate is that, and is it altitude or radius? Would be nice to have better numbers.....;-)

Your ballute+chute idea sounds plausible - watchout SpaceX don't steal it!

Cheers,
Brian
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Old 04-20-2018, 07:04 PM   #15
Marijn
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Hi Brian,
So you were right on them doing a flyback. And launching into a low parking orbit. The reporter said 250x250km. And no giant party balloons or bouncing castle tricks.

Wat do you think about the numbers after the launch? I ran the scenario against the SpaceX webcast a few times. All events up to MECO match up perfectly. But there are more than 30 seconds between the touchdown times of the 1st stage when launching into a 250km orbit, and 45 seconds difference when launching into 250x250km.

It looks to me that the actual 1st stage flips around much more quickly after separation than the simulation in Orbiter and it did deploy its gridfins rather early as well. The whole move seemed very aggresive.

Can you consider these events?
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