Author Topic: Vulcan VC2S V001 - Peregrine Lander - CCSFS SLC-41 - 8 Jan 2024 (07:18 UTC)  (Read 441962 times)

Online gongora

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I don't know what posts you are referring to.  The flight profile a few posts back from ULA shows Centaur doing the TLI burn.  I have no idea where you're getting the part about Peregrine raising perigee before doing some TLI burn.  Why would you do that for a Lunar transfer?  FCC documentation from both ULA and Astrobotic says that ULA is doing the TLI burn.

If you are referring to this post it is not definitive whether or not the second or third CES is a TLI burn and the task of that third burn.
If you are referring to a different post, please link it.

Yes, that's the one I was referring to, and it's the SECOND burn that puts it in TLI.  The C3 value given for Peregrine at separation is for TLI.  The third burn is Centaur disposal.

Unfortunately ULA was sloppy updating their latest filing and didn't remove the Kuiper sats that have already been launched, but this is the general idea:
Quote
Cert-1 Launch
The Peregrine mission will be launched from the Eastern Range and utilize a trajectory design
consisting of a two Centaur burn ascent to spacecraft separation. One Earth-relative trajectory
will be used through the first Centaur engine burn (MES1) for all launch opportunities. At
MECO1, the Centaur is in a circular 500 km park orbit at an inclination of 30 degrees. This orbit
is sustained through Kuiper separation. After MECO1, polynomial RAAN steering is activated,
and the Centaur flies a varying mission profile for each launch opportunity to reach TLI. These
consist of different coast lengths along the MECO1 orbit. At MECO2, the orbit parameters differ
between the three different coast length profiles. The short coast will have a perigee/apogee
altitude of 494.20/370,872.31 km and an inclination of 30.08 degrees, the medium coast will
have a perigee/apogee altitude of 487.93/395,521.85 km and an inclination of 30.09 degrees, and
the long coast will have a perigee/apogee altitude of 493.43/364,004.18 km and an inclination of
30.07 degrees. The variation in orbital parameters continues to Peregrine separation. At
Peregrine separation, the short coast will have a perigee/apogee altitude of 494.41/382,527.97
km and an inclination of 30.08 degrees, the medium coast will have a perigee/apogee altitude of
487.61/402,774.56 km and an inclination of 30.09 degrees, and the long coast will have a
perigee/apogee altitude of 493.98/363,946.57 km and an inclination of 30.07 degrees. Spacecraft
separation is followed by a third main engine burn (MEB3) to place Centaur in a hyperbolic
disposal orbit, a demonstration of the reaction control system (RCS), and blowdown of the
remaining propellants and hydrazine depletion. Following the completion of these events, Endof-Mission (EOM) occurs.

This is the description on Astrobotic's FCC filings (which are really a mess, I don't see an approved FCC filing for them yet.)
Quote
Astrobotic’s Peregrine Mission 1 will deliver government and commercial science payloads
and instruments to the surface of the Moon. Peregrine will be delivered to a trans lunar
injection orbit on a ULA Vulcan launch vehicle. Once separated from the Vulcan Centaur
upper stage, Peregrine’s trajectory will include one elliptical loop around the Earth


This is from Astrobotic's FCC filings. The possible small perigee raise is just to pass through a less crowded altitude when going back around Earth.
Quote
Peregrine is a lunar lander which briefly passes through LEO and GEO altitudes twice during its flight to
the Moon- once at initial separation from the launch vehicle, and a second time during a single phasing
loop between the Earth and the Moon.

Peregrine will be launched directly into a 30-degree inclination TLI orbit that has its apogee at lunar
distance and perigee at 500km. Once separated from the launch vehicle, Peregrine will gain altitude
quickly without needing to perform any propulsive maneuvers, exiting the LEO debris zone within 10
minutes post-separation.

The first propulsive maneuver performed by the lander will not occur until at least 12 hours postseparation,
where there is a placeholder for a possible trajectory correction maneuver.
Once Peregrine reaches lunar distance, it will return to perigee once more, in a phasing loop. Astrobotic
plans to perform a perigee raise maneuver (PRM) at apogee to ensure the phasing loop perigee is at least
600km in altitude. Depending on the exact date of launch, the natural perigee of this phasing loop may
already be up to 2500km without performing a PRM. In any case, Astrobotic’s analysis indicates that we
have the DeltaV budget on any potential launch date to perform a PRM that will raise our perigee to at
least 600km.

The decision to target a 600km minimum perigee was reached via a combination of analysis of the current
debris field at different altitudes as well as a general concern about the increasing number of satellites at
550km and how crowded that altitude may become by late 2021.

Online gongora

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I don't know what posts you are referring to.  The flight profile a few posts back from ULA shows Centaur doing the TLI burn.  I have no idea where you're getting the part about Peregrine raising perigee before doing some TLI burn.  Why would you do that for a Lunar transfer?  FCC documentation from both ULA and Astrobotic says that ULA is doing the TLI burn.

If you are referring to this post it is says:
Quote
Peregrine Orbit At Separation
Peregrine altitude: 494.4 km  C3 = -2.06 km^2/s^2
Inclination: 30.07 deg            Flight azimuth: 90.0 deg
So yes, the Centaur does the TLI
For those of us like me who are clueless, can you explain how you determined that this is a TLI instead of an HEO? I do not disbelieve you, I just don't know how to do the math.

I googled C3 value for TLI.  I don't know the math either.

edit: TLI is to send something into a HEO orbit that goes out to lunar distance.
« Last Edit: 12/05/2023 05:40 pm by gongora »

Offline Apollo-phill

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This is image from Astrobotic launch info package being given to aid watching/ following launch and mission from Cape Canaveral in December.

It shows Peregrine having separated from Vulcan Centaur V some time before Peregrine undertakes TLI at perigee

But a detailed Flight Plan would be great please Astrobotic🚀 🤠

Offline Apollo-phill

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Wow, that IS SOME Peregrine HEO orbit as the Moon apogee distance from Earth on 1 January 2024 is 404,909 km.

Perigee on 16 January 2024 is 362,267 km.



« Last Edit: 12/06/2023 01:17 pm by Apollo-phill »

Offline John Santos

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This is image from Astrobotic launch info package being given to aid watching/ following launch and mission from Cape Canaveral in December.

It shows Peregrine having separated from Vulcan Centaur V some time before Peregrine undertakes TLI at perigee

But a detailed Flight Plan would be great please Astrobotic🚀 🤠
The image you attached is too low res to read the text, but from the description, the initial orbit raising maneuver, performed by the Centaur, doesn't directly take Peregrine to the moon.  It reaches the Moon, or comes close enough to enter lunar orbit, on the SECOND orbit, which is highly elliptical and whose apogee is very close to the Moon's distance from Earth.  I suspect an important reason for this is so there is no chance the Centaur will impact the Moon.  The text quoted above says that they may, if needed perform a slight perigee raise burn at apogee, to make sure Peregrine is above most of the LEO debris (at least 600km, but the natural perigee may be as high as 2500km), and if it is above 600km, this burn would be unnecessary.  I'm not really clear on this, but I think there may be a second firing, at perigee to correct the course and maybe to raise apogee all the way to lunar distance.

The average distance of the Moon is 384,000km and the initial TLI orbit, depending on which window is used, ranges in apogee from 363,000 to 402,000 km.  Whether this is sufficient to reach the Moon's Hill Sphere, which would be necessary in order to enter lunar orbit, depends on the position of the Moon in its elliptical orbit at the time of the second apogee.  This is why I think a perigee burn in addition to the apogee burn might be needed.

Both the apogee burn (at the first apogee) and the perigee burn (if necessary) would be performed by Peregrine long after it separates from the Centaur, and would require very little delta V.  Almost all the TLI energy comes from the Centaur, not from Peregrine's onboard propulsion, so it is misleading to imply that Peregrine and not Centaur will perform the TLI.

Offline Comga

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I don't know what posts you are referring to.  The flight profile a few posts back from ULA shows Centaur doing the TLI burn.  I have no idea where you're getting the part about Peregrine raising perigee before doing some TLI burn.  Why would you do that for a Lunar transfer?  FCC documentation from both ULA and Astrobotic says that ULA is doing the TLI burn.

If you are referring to this post it is says:
Quote
Peregrine Orbit At Separation
Peregrine altitude: 494.4 km  C3 = -2.06 km^2/s^2
Inclination: 30.07 deg            Flight azimuth: 90.0 deg
So yes, the Centaur does the TLI
For those of us like me who are clueless, can you explain how you determined that this is a TLI instead of an HEO? I do not disbelieve you, I just don't know how to do the math.

I googled C3 value for TLI.  I don't know the math either.

edit: TLI is to send something into a HEO orbit that goes out to lunar distance.

I deleted that post because I realized that my statement was not certain.
I (used to) know some of the math, particularly how to calulate the velocity at apogee and perigee for an Earth orbit.
From that one can calculate the delta V from a low circular orbit at radius r1 to an r1 by r2 orbit as
DeltaV=Sqrt(mu/r1)*(Sqrt(2*r2/(r1+r2))-1)
with Mu=3.99E+05 km^3/sec^2
Stretching it absurdly, to go from a circular 600 km orbit to one 600 by 40 million km requires a delta-V of 3.13 km/sec
Going from a 300 km circular orbit requires a delta-V of 3.20 km/sec, so this is not strongly dependent on parking orbit altitude.
That can be used as a basis for C3=0
To go to an orbit of 600 by 400,000 km, roughly the orbit of the Moon, takes a delta V of 3.130 km/sec, so only 1 m/s difference from C3=0
To go to an orbit of 600 by 14,500 km takes a delta V of 1.696 km/sec
The square of the difference is 2.06 km^2/sec^2
So C3=-2.06 km^2/sec^2, the release orbit of the Peregrine, would be far below TLI.

Somebody please check my math.

edit: Thank you Lou, for going at the math properly and switching the conclusion back to where C3=-2.06 km^2/sec^2 with a 600 km apogee does mean that the Centaur has done the TLI
« Last Edit: 12/07/2023 11:24 pm by Comga »
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Offline Phil Stooke

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Astrobotic has said in the past (I think it's in the Payload Users Guide) that the trip to the Moon can take anywhere from 5 to 35 days, so obviously there is not just one way to get there.  Various versions of phasing orbits and lunar operations are possible.  So you can't take any previously published flight plan and say that's what it will be.  And Astrobotic doesn't know exactly when it will launch yet, so it's still not possible to have a definitive flight plan.  You might have to wait for launch to get the plan you need.

Online gongora

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Both Astrobotic and ULA have said quite unambiguously in their filings about the flight that the launch vehicle is doing the TLI burn.  This isn't some random notional mission.

Online LouScheffer

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For those of us like me who are clueless, can you explain how you determined that this is a TLI instead of an HEO? I do not disbelieve you, I just don't know how to do the math.
Here's the calculation turning C3 into apogee.  It's only a few steps:
#1:   a = -u/C3   where a is the semi-major axis, and u = gravitational constant = GM = 398600.435507 km^3/sec^-2 for Earth, from a JPL website.  This follows from the definition of specific orbital energy.

#2:  apogee = 2*a - 2*Re - p  where Re is the radius of the Earth, and p = perigee.  This is because the semi-major axis is the average of apogee and perigee, defined relative to Earth's center.

So plug in C3 = -2.06 to get a=193,495 km.   Then plug in Re = 6371 km, and p=600 km, to get apogee = 373,649 km.

Since the moon's distance ranges from about 363,000 km to 405,000 km, the apogee is very close to the altitude of the moon.
« Last Edit: 12/06/2023 05:23 am by LouScheffer »

Offline sdsds

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Here's the calculation turning C3 into apogee. [...]

Thanks very much for providing this calculation. I used the Vulcan Cert-1 ULA page to get the planned spacecraft separation parameters (see attached), and essentially reproduced your result.

I also calculated the C3 value for a hypothetical circular parking orbit at the altitude of the spacecraft separation perigee, and values for the Moon's orbit to calculate the C3 value for an orbit like that of the Moon.

That's not the actual mission plan, and still it puts some numbers on the relative contributions of the Centaur and the spacecraft. Centaur imparts 98.2% of the necessary energy and the spacecraft imparts 1.8%.
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Online Robert_the_Doll

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https://twitter.com/ulalaunch/status/1732412596459073581

Quote
#VulcanRocket is on the move today in our #CountdowntoVulcan! The #Cert1 rocket is traveling from the Vertical Integration Facility to Space Launch Complex-41 to begin Wet Dress Rehearsal activities that include a practice countdown and fueling exercise. http://bit.ly/vulcan_cert1


Offline Apollo-phill

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With the FCC filings that gongora pointed to and the calcs done here by sdsds,et al, then its  Centaur V ( not Peregrine)  doing TLI major burn part with the later Peregrine burn tweaking it.

Reason I am interested is that I have two moonmail  boxes on Peregrine 1 (- been waiting since 2015 and was  originally Griffin mission ) and local media doing live coverage with me on Christmas Eve. But with festivities they'll only give so much airtime up until TLI .So as accurate as possible TLI time required  as important so  media knows airtime needed.

If launch gets delayed on 24th or into 25th or 26th unlikely to get live coverage -  just  recorded news highlight piece.

 Perhaps been spoiled by the  reams of detailed  NASA mission information released during Apollo,STS flights
in 60-90s. Maybe have to get used to fewer detailed releases from commercial operators - especially where they only have small number of employees ?


Phill






Offline FutureSpaceTourist

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https://twitter.com/gregscott_photo/status/1732765340671635503

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More tower construction, new tanks & work on Hangar X at #SpaceX's Roberts Rd on yesterdays flyover. Work on pad LC39B, New Amazon Project Kuiper building progressing, work on the new Mobile Launcher, #ULA's Vulcan stands on the test stand, and a new #BlueOrigin crane & New Glenn port stand at Port Canaveral. 1/2

Offline zubenelgenubi

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All three December launch windows: 🪟
SFN Three robotic missions target Moon landings over one week in January, December 6, by Will Robinson-Smith
Quote
The next lander to launch and the last one scheduled to land in January is Astrobotic’s Peregrine lunar lander. Liftoff aboard a United Launch Alliance Vulcan rocket is set for 1:49 a.m. EST (0649 UTC) on Dec. 24. If needed, there are backup opportunities at 1:53 a.m. EST (0653 UTC) on Dec. 25 and 2:08 a.m. EST (0708 UTC) on Dec. 26.

The mission will launch the lander on a translunar injection.
<snip>
According to a Nov. 14 presentation by Dr. Joel Kearns, NASA Deputy Associate Administrator for Exploration, the landing window for the Peregrine Mission-1 landing is at 3:30 a.m. EST (0830 am UTC) on Jan. 25.

Quote from: Jeff Foust tweet,  Dec 14
Slides from a presentation from NASA's Joel Kearns show a Jan. 19 or 21 landing for the IM-1 lunar lander assuming a launch Jan. 12-16, and a Jan. 25 landing for Peregrine if it launches Dec. 24-26. And that Peregrine launch will be in the middle of the night at the Cape…
« Last Edit: 12/07/2023 11:41 pm by zubenelgenubi »
Support your local planetarium! (COVID-panic and forward: Now more than ever.) My current avatar is saying "i wants to go uppies!" Yes, there are God-given rights. Do you wish to gainsay the Declaration of Independence?

Online edkyle99

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This is image from Astrobotic launch info package being given to aid watching/ following launch and mission from Cape Canaveral in December.

It shows Peregrine having separated from Vulcan Centaur V some time before Peregrine undertakes TLI at perigee
I nominate this as the worst space mission graphic of the year.  It is wrong, and, worse, it caused discussion here!

 - Ed Kyle
« Last Edit: 12/08/2023 01:53 am by edkyle99 »

Offline Steven Pietrobon

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Updated version of press kit with the Mission Profile.
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline sdsds

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I nominate this as the worst space mission graphic of the year.  It is wrong, and, worse, it caused discussion here!

My trajectory tools aren't the best, yet I believe the attached graphic more accurately shows — in the rotating frame — the type of trajectory Peregrine will take from the vicinity of Earth to the vicinity of the Moon.
« Last Edit: 12/08/2023 04:49 am by sdsds »
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Offline FutureSpaceTourist

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https://twitter.com/ulalaunch/status/1733123003276280310

Quote
The inaugural United Launch Alliance #VulcanRocket is standing atop Space Launch Complex-41 at Cape Canaveral to undergo an extensive Wet Dress Rehearsal ahead of #Cert1.

Learn more about this test in the #CountdowntoVulcan:

https://blog.ulalaunch.com/blog/vulcan-cert-1-dress-rehearsal-of-launch-day-planned

Quote
Vulcan Cert-1: Dress rehearsal of launch day planned
December 8, 2023

The inaugural United Launch Alliance (ULA) Vulcan rocket rolled out to the Space Launch Complex (SLC)-41 pad at Cape Canaveral Space Force Station on Dec. 6 to undergo an extensive practice countdown.

Known as a Wet Dress Rehearsal (WDR), ULA is preparing to conduct a full day-of-launch test to ensure the new rocket, pad systems and launch team are ready for the first Vulcan mission. The WDR exercises the hardware, procedures and the people to reduce the risk of a delay on launch day.

The rehearsal follows the tightly scripted sequence by rolling the Vulcan from the Vertical Integration Facility (VIF) to SLC-41, performing the entire countdown operation to fuel the rocket with cryogenic propellant and returning the vehicle to the VIF afterwards.

The countdown begins before sunrise under the guidance of the ULA launch conductor from the Advanced Spaceflight Operations Center (ASOC), located about four miles (6.4 km) from the pad.

The rocket stages are powered up, avionics tested and final preps to ground systems accomplished. That enables the ULA launch director to give approval for fueling process.

The launch team configures the Vulcan Centaur for cryogenic loading and approximately one million pounds (454,000 kg) of methane, liquid oxygen and liquid hydrogen into the rocket's tanks using the same procedures that will be executed on the actual launch day.

With the rocket filled up, permission will be given to enter terminal count at T-minus 7 minutes. The final phase of the countdown pressurizes the rocket, arms various systems and transitions the vehicle to internal power.

At T-minus 25 seconds, engineers confirm final readiness by declaring "Go Vulcan," "Go Centaur V," "Go Cert-1." The count finishes just prior to ignition time.

The rocket is then safed and cryogenic tanks drained in preparation to return to the VIF.

Once the WDR operations are satisfactorily accomplished, the encapsulated payload will be delivered to the VIF for hoisting atop the launch vehicle to begin combined preparations for launch.

The Certification-1 test flight will launch Astrobotic’s  Peregrine lunar lander on a commercial flight to the Moon and carry the Celestis memorial payload into deep space. Launch is targeted for Dec. 24.

First photo caption:

Quote
The inaugural Vulcan rocket stands atop Space Launch Complex-41 for the Wet Dress Rehearsal. Photo by United Launch Alliance
« Last Edit: 12/08/2023 12:59 pm by FutureSpaceTourist »

Offline FutureSpaceTourist

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https://twitter.com/astrobotic/status/1732773834372079816

Quote
Q: How do you make sure a lunar lander is able to survive the violent rattling of a rocket launch into space? A: You shake the &#$% out of it on Earth. This is called vibrational or “vibe” testing of a spacecraft. 1/

If the frequencies of launch accidentally match a resonance frequency of the spacecraft (which is based on its size, construction, and composition) then launch vibrations could shake the lander apart! 🙃 2/

Fortunately, excellent frequency data, rigorous structural analysis of the Peregrine spacecraft by Astrobotic engineers, and a highly accurate Structural Test Model (STM) have ensured that won’t happen 👌 3/

So what’s an STM? Basically a crash test dummy for a spacecraft. An STM is a bolt-for-bolt model built with the same dimensions and mass distribution, so it will respond like the final build (or “flight model”) would during testing. 4/

Astrobotic provided an STM of Peregrine for vibe testing by Dayton T Brown, Inc., where it was shaken at the exact frequencies the rocket would subject it to during launch. This will ensure our lander and its payloads survives the trip to space, safe and sound 5/

Once we had confirmation that our STM could handle launch vibrations, we bunkered down to build the real deal. But juuuuuust to make sure that our lander would survive both in theory AND in practice, we sent the flight model off to get vibration tested as well. /6

Our lander's flight model underwent successful testing in Dec 2022, months in advance of our impending launch. Thanks to this testing, we know it’s going to be good “vibes” only from here on out 😎👍 end/

https://twitter.com/astrobotic/status/1733158707721130119

Quote
Looping back to yesterday's🧵to share a few photos! Here's Peregrine's STM in our cleanroom. Note the mass models of payloads + other equipment on its hex frame placed in the precise locations that they are secured on the flight model

Offline FutureSpaceTourist

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https://twitter.com/ulalaunch/status/1733177086586523774

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It is WDR day at SLC-41 in our #CountdownToVulcan! Cryogenic propellant loading operations are underway on both the #VulcanRocket booster stage and Centaur V upper stage to simulate a launch day and test the rocket and pad systems.

#Cert1 launch info: bit.ly/vulcan_cert1

 

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