SpaceX F9 : Nusantara Satu (PSN VI)/GTO-1/SpaceIL : Feb. 21/22, 2019: Discussion

[jpo234]

An interesting detail on one of the payloads:

https://twitter.com/PeterGuggenbach/status/1094943898407968768

We are going to the moon! A 3D engine mount from RUAG Space will be the first 3D printed part on the moon. Our 3D part will support landing and lift off of Lunar Lander from @TeamSpaceIL. Congrats to our incredible engineers!

What "lift off"?

[Electric Paint]

An interesting detail on one of the payloads:

https://twitter.com/PeterGuggenbach/status/1094943898407968768

We are going to the moon! A 3D engine mount from RUAG Space will be the first 3D printed part on the moon. Our 3D part will support landing and lift off of Lunar Lander from @TeamSpaceIL. Congrats to our incredible engineers!

What "lift off"?

IIRC, the lander is supposed to perform a short 500m hop, at some point after initial touchdown.

[flyright]

An interesting detail on one of the payloads:
...

What "lift off"?

IIRC, the lander is supposed to perform a short 500m hop, at some point after initial touchdown.

The lander was designed to perform the 500m hop as a requirement for the now expired Google Lunar X prize. I don't know if they still intend to do the hop, but it would be awesome if they did.

edit: trimmed quote

[gongora]

Please trim quotes.  We don't need the same Tweet showing up several times in a row.

[scr00chy]

https://twitter.com/StephenClark1/status/1095009451935961088

Rideshare launch provider @SpaceflightInc confirms identify of second piggyback payload riding on SpaceX’s next Falcon 9 launch. SpaceIL’s Beresheet lunar lander and the Air Force Research Lab’s S5 smallsat will launch with Indonesia’s PSN 6 comsat no earlier than Feb. 21.]Rideshare launch provider @SpaceflightInc confirms identify of second piggyback payload riding on SpaceX’s next Falcon 9 launch. SpaceIL’s Beresheet lunar lander and the Air Force Research Lab’s S5 smallsat will launch with Indonesia’s PSN 6 comsat no earlier than Feb. 21.

More information about the payload here.

[scr00chy]

Can somebody please explain to me what the planned launch profile for this mission is? I can't seem to find any conclusive information. This is what we know (correct me if I'm wrong):

-Total payload mass is around 5400 kg (4735 kg Nusantara Satu + 600 kg Beresheet + 60–150 kg S5 microsat)
-Once the Falcon 9 reaches GTO, it will separate SpaceIL’s lunar lander with a custom separation system at an altitude of 60,000 kilometers
-Beresheet is mounted on top of PSN-6 so it presumably cannot be released after PSN-6
-Falcon 9 first stage is planned to be recovered (there is an FCC licence for ASDS landing)

So, with all that, what is the launch profile supposed to look like? The rocket needs to carry this pretty heavy payload to an orbit with 60,000 km apogee while still allowing for ASDS landing of the first stage. When looking at other GTO launches, it doesn't seem possible. What am I missing?

Some ideas:

-The information about deployment at 60,000 km is incorrect
-Launch is expendable
-The mass numbers are wrong
-Little to no inclination change and/or low perigee buys you enough delta-v to raise the apogee high enough? (sorry if this is nonsense, I'm still confused by orbital mechanics)

[jcm]

For the record,  "Nusantara Satu" translates exactly to "one archipelago" (word order gets reversed so Satu which means 1, comes first) without "Indonesian" in it.

I asked my wife, a native Indonesian and teacher of Bahasa Indonesia (Indonesian language) to non Indonesian speakers, and that's what she told me. The material in the intro post isn't quite right, it has too much stuff in it.

That's very odd since they have also talked about a second sat, Nusantara Dua :

https://kumparan.com/@kumparantech/april-2020-psn-luncurkan-satelit-nusantara-dua-pengganti-palapa-d-1548246721064822411

[jcm]

Presumably the S5 satellite uses the SSL PODS attach system like  Hispasat 30W-6/PODSAT?

I can't find any details of Beresheet's propulsion system: just that it is `bipropellant'.  So,  N2O4/UDMH?
Any info on thrust and Isp and so on?

[scr00chy]

Presumably the S5 satellite uses the SSL PODS attach system like  Hispasat 30W-6/PODSAT?

Yes, it will stay attached to PSN-6 until right before GEO

[Lar]

For the record,  "Nusantara Satu" translates exactly to "one archipelago" (word order gets reversed so Satu which means 1, comes first) without "Indonesian" in it.

I asked my wife, a native Indonesian and teacher of Bahasa Indonesia (Indonesian language) to non Indonesian speakers, and that's what she told me. The material in the intro post isn't quite right, it has too much stuff in it.

That's very odd since they have also talked about a second sat, Nusantara Dua :

https://kumparan.com/@kumparantech/april-2020-psn-luncurkan-satelit-nusantara-dua-pengganti-palapa-d-1548246721064822411

Doesn't contradict what I said. My point is that "Indonesian" isn't part of the name, except allegorically (in that Indonesia occupies the vast majority of the largest archipelago in the world) because nusantara just means collection of islands. The header got fixed by gongora to remove that.

satu dua tiga   empat lima enam tujuh   delapan sembilan sepuluh
one  two three four    five   six     seven eight      nine         ten

Indonesian is an interesting language. It lacks tense, plural, and gender for the most part, and many words are overloaded. Kepuluan means both island and archipelago depending on context. Pulua just means island and nusantara just means archipelago.

[ZachS09]

Can somebody please explain to me what the planned launch profile for this mission is? I can't seem to find any conclusive information. This is what we know (correct me if I'm wrong):

-Total payload mass is around 5400 kg (4735 kg Nusantara Satu + 600 kg Beresheet + 60–150 kg S5 microsat)
-Once the Falcon 9 reaches GTO, it will separate SpaceIL’s lunar lander with a custom separation system at an altitude of 60,000 kilometers
-Beresheet is mounted on top of PSN-6 so it presumably cannot be released after PSN-6
-Falcon 9 first stage is planned to be recovered (there is an FCC licence for ASDS landing)

So, with all that, what is the launch profile supposed to look like? The rocket needs to carry this pretty heavy payload to an orbit with 60,000 km apogee while still allowing for ASDS landing of the first stage. When looking at other GTO launches, it doesn't seem possible. What am I missing?

Some ideas:

-The information about deployment at 60,000 km is incorrect
-Launch is expendable
-The mass numbers are wrong
-Little to no inclination change and/or low perigee buys you enough delta-v to raise the apogee high enough? (sorry if this is nonsense, I'm still confused by orbital mechanics)

scr00chy, I have some sources that list the actual mass numbers of all three payloads:

https://space.skyrocket.de/doc_sdat/s5.htm
S5 weighs 60 kilograms (~132 pounds).

https://space.skyrocket.de/doc_sdat/psn-6.htm
Nusantara Satu weighs 4,735 kilograms (~10,439 pounds).

https://www.bbc.com/news/world-middle-east-44777305
Beresheet weighs 585 kilograms (~1,290 pounds).

Altogether, the total payload mass is 5,380 kilograms (~11,861 pounds). Also, I'm still under the assumption that the booster WILL land on the drone ship while the final geosynchronous transfer orbit's apogee WILL be 60,000 kilometers (might be a bit higher or lower depending on how much delta-v Stage 2 will use up).

[LouScheffer]

So, with all that, what is the launch profile supposed to look like? The rocket needs to carry this pretty heavy payload to an orbit with 60,000 km apogee while still allowing for ASDS landing of the first stage. When looking at other GTO launches, it doesn't seem possible. What am I missing?

Some ideas:

-The information about deployment at 60,000 km is incorrect
-Launch is expendable
-The mass numbers are wrong
-Little to no inclination change and/or low perigee buys you enough delta-v to raise the apogee high enough? (sorry if this is nonsense, I'm still confused by orbital mechanics)

I agree that one of these seems wrong:

Lack of inclination change is insufficient.  Es'hail 2 , at 5300 kg, reduced inclination by 2 degrees.  If they skipped that, they would have about 50 m/s more, only enough for a 40,000 km apogee.  Likewise low perigee burns can help slightly , but not nearly enough.  So it's not that.

Deployment not at 60,000 km could be wrong.  The source states "60,000 kilometers, or 37,282 miles,".  GTO orbit is about 36,000 km, so maybe there is a communication/units error.

Another possibility is "burn to depletion".  Most launches target an explicit orbit.  To do that, they need to have slightly more fuel than they really need, typically something like 1%. (So if your performance is normal you have 1% left.  If's it's 3-sigma bad, you have barely enough fuel.  If performance is 3-sigma good, you have 2% remaining.)  If you don't care about the exact orbit, you can use these last reserves by simply burning until the fuel runs out.   This reduces the needed delta-AV for the payload, but it's a pain in the butt since you can't plan any of your post-launch maneuvers in advance, since you don't know what orbit you'll get. 

From fitting to performance curves, SpaceX normally stops with the second stage, with residuals, at 5.5t.  If they burn the last ton (a little more than 1%) of the propellants, they will get an additional 300 m/s, enough for a 67,000 km apogee.   So if SpaceX tries this, in the worst case they get about 40,000 km.  In the average case, about 67,000 km, and in the best case about 150,000 km.

But if I was Beresheet is seems risky to count on this, plus they would need to get Nusantara and S5 to agree.  So overall I suspect the unit conversion error.

[OccasionalTraveller]

Beresheet would want zero inclination correction. The Moon's orbit is inclined ~5.14° above the ecliptic - which is ~23.4° above the Earth's equatorial plane (equal to the tilt of the Earth's axis). That comes to ~28.5°, which is - not entirely coincidentally - the inclination you get by launching due east from Cape Canaveral.

Any inclination change to assist Nusantara would have to be undone by the lander. So I would expect a greater apogee in preference to inclination change.

[Lar]

Beresheet would want zero inclination correction. The Moon's orbit is inclined ~5.14° above the ecliptic - which is ~23.4° above the Earth's equatorial plane (equal to the tilt of the Earth's axis). That comes to ~28.5°, which is - not entirely coincidentally - the inclination you get by launching due east from Cape Canaveral.

Any inclination change to assist Nusantara would have to be undone by the lander. So I would expect a greater apogee in preference to inclination change.

That implies that we are likely to see an instantaneous or very short launch window  (that moves by 1/365.24xx of a day each day)I think? because isn't the inclination you get dependent on where in the earth's rotation you are? Naiive guess work.

[Alexphysics]

Beresheet would want zero inclination correction. The Moon's orbit is inclined ~5.14° above the ecliptic - which is ~23.4° above the Earth's equatorial plane (equal to the tilt of the Earth's axis). That comes to ~28.5°, which is - not entirely coincidentally - the inclination you get by launching due east from Cape Canaveral.

Any inclination change to assist Nusantara would have to be undone by the lander. So I would expect a greater apogee in preference to inclination change.

Do I have to remember that InSight went to Mars from a polar orbit? You don't need to match the other object's inclination to get there, you just need to intersect your orbit with the orbit of that object and get to that intersection at around the same time that object gets there. The lander will land TWO MONTHS after launch so they will have a lot of time to perfectly calculate what they need to do to get to the point where they intersect the orbit and to get there at the appropiate time.

[scr00chy]

That implies that we are likely to see an instantaneous or very short launch window  (that moves by 1/365.24xx of a day each day)I think? because isn't the inclination you get dependent on where in the earth's rotation you are? Naiive guess work.

Ben Cooper says "The launch window likely stretches about 32 minutes."

[Lar]

That implies that we are likely to see an instantaneous or very short launch window  (that moves by 1/365.24xx of a day each day)I think? because isn't the inclination you get dependent on where in the earth's rotation you are? Naiive guess work.

Ben Cooper says "The launch window likely stretches about 32 minutes."

seems short to me (2% of a day, more or less)...

[ZachS09]

Quick question:

Will SpaceX recover the fairings for next week's launch (Fairing 2.0), or will they leave them in the ocean (Fairing 1.0)?

Also, has SpaceX determined which booster they will use?

[gongora]

Also, has SpaceX determined which booster they will use?

Yes.  (Now for us to determine which booster they'll use.)

[ZachS09]

Also, has SpaceX determined which booster they will use?

Yes.  (Now for us to determine which booster they'll use.)

I'm guessing they will fly B1048 for a third time, given that it was seen in the LC-39A HIF alongside B1051.