91

SpaceX Starship Program / Re: Starship Flight 5 DISCUSSION : Starbase TX : NET 13 Oct 2024

« Last post by ulm_atms on 10/12/2024 06:03 pm »

HAHAHAHA....."Pending regulatory approval." for the loading screen. 

92

Missions To The Moon (HSF) / Re: NASA's Artemis Program Updates and Discussion Thread 5

« Last post by DanClemmensen on 10/12/2024 05:55 pm »

Why would SpaceX do that? Where would it fit into SpaceX' plans? As far as I can tell SpaceX wants to use Starship for any BLEO missions, and Starship it supposed to use a refractory reusable TPS, not an ablative TPS. Perhaps you are thinking of some replacement for SLS/Orion that includes a Dragon returning from cislunar space?

Actually I think that Dragon is a potential replacement for Orion.
Orion usable space: 316 cubic feet (8.95 cubic meters).
Dragon usable space: 328 cubic feet (9.30 cubic meters), 12 cubic feet more than Orion.

Thanks for the clarification. Basically, you think it is easier to replace Orion than it is to fix its heat shield. That sounds right to me. My concern is that the approach you outlined will require a fair amount of new development, which may take as much or more time as fixing Orion's heat shield, so we are adding years to the Artemis III schedule. You did not mention which LV would be used: do you have a recommendation?

I still prefer changing the mission architecture entirely that eliminates SLS and Orion. Use Dragon for Earth-LEO and LEO-Earth, use (refuelled) Starship for LEO-NRHO-LEO, and use Starship HLS for NHRO-Moonsurface-NRHO. This does not require any new hardware design beyond what is already needed for Artemis III, because the transit Starship can be a separate instance of Starship HLS.

93

Spaceflight Entertainment and Hobbies / Re: Lost Starship Found: The Enterprise Model Story

« Last post by Blackstar on 10/12/2024 05:44 pm »

There is a thread for this. The link should really be posted there:

https://forum.nasaspaceflight.com/index.php?topic=60731.0

94

SpaceX Falcon Missions Section / Re: SpaceX FH - Europa Clipper - KSC LC-39A - 14 October 2024 (16:06 UTC)

« Last post by FutureSpaceTourist on 10/12/2024 05:35 pm »

Updated L-2 launch weather forecast now 90% GO

95

Advanced Concepts / Re: Energy shield or force field made of plasma as Heatshield

« Last post by Jonathan_Blatter on 10/12/2024 05:15 pm »

There are some studies on something called magnetosphere aerobraking.  IIRC, the problem is that they work best with very high velocities (higher than you would get on a return from LEO. There are some ideas on seeding the plasma artificially but that then comes with other problems. I still find the concept extremely interesting and I wished they would explore it more.

The link you posted seems to be about something to protect against microwaves, which I don't think is applicable here.

Yeah the magnetosphere aerobraking is one thing, but I thing the concept coult help a heatshild, so that the hot plasma son not touch the reentry vehicle.
Is there sombody that has expieriens with plasma. plasma welding and maybe made som exoeriments in that feeld?

96

Missions To The Moon (HSF) / Re: NASA's Artemis Program Updates and Discussion Thread 5

« Last post by clongton on 10/12/2024 05:09 pm »

If I remember correctly, SpaceX modified the original pica formulation and renamed it PicaX to make Dragon's heatshield capable of EDL at lunar and interplanetary return velocity. It was in 2016 that SpaceX announced the Red Dragon program for a Mars Sample Return mission. PicaX was developed to support that. Anyone else remember this? If so, I think this would be a good time to test that for real.

Are you proposing that NASA should test a PicaX heat shield on Orion, or that SpaceX should test a Dragon on a high-velocity return mission?

If Orion, what does the test mission look like? Uncrewed Artemis I re-run?

If Dragon, how would this fit into Artemis?

For Dragon, not Orion. And it would be less than optimal to try to fit anything into Artemis. It would take forever. SpaceX should fly a heatshield demo on its own dime.

Why would SpaceX do that? Where would it fit into SpaceX' plans? As far as I can tell SpaceX wants to use Starship for any BLEO missions, and Starship it supposed to use a refractory reusable TPS, not an ablative TPS. Perhaps you are thinking of some replacement for SLS/Orion that includes a Dragon returning from cislunar space?

(Separately, according to Wikipedia Dragon now uses a newer version called PICA-3 instead of the earlier PICA-X, but I have zero insight into the details).

Actually I think that Dragon is a potential replacement for Orion.

Usable Internal Volume
Orion usable space: 316 cubic feet (8.95 cubic meters).
Dragon usable space: 328 cubic feet (9.30 cubic meters), 12 cubic feet more than Orion.

Life Support
In terms of life support capability, the Dragon spacecraft is capable of sustaining crew for up to 7 days by itself, while Orion (without the service module) only up to 1 day.
Orion's service module (which Dragon does not have) carries the majority of the consumables, extending the capsule's life support from 1 day to 21 days. While Dragon does not have a service module, it does have an empty trunk, which could could relatively easily be converted to a service module to supply the consumables. That would extend Dragon's capability to at least equal Orion's, if not exceed Orion's capability.

Propulsion
Orion's propulsion (like Apollo) is provided by propellant and engine in the service module. It has no other independent propulsion capability.
Dragon's propulsion is provided by Super Dracos mounted within the spacecraft itself, providing the spacecraft with limited independent propulsion. But propellant and Super Dracos could also be included in a Trunk that has been modified to function as a Service Module, to provide the TLI, LOI and TEI burns.

Reentry
PICA-3 can withstand temperatures in excess of 2,400°C (4,350°F). This high thermal tolerance makes it effective for spacecraft re-entering Earth’s atmosphere at very high velocities. This material was specifically developed for high-speed re-entries, like the now cancelled Red Dragon program making a direct reentry from Mars, and its properties are designed to handle the intense heat generated by returning from deep space. PICA-3 is a newer material than Avcoat and has been used in high-speed re-entry missions, such as NASA's Stardust mission, which returned at one of the highest re-entry speeds ever recorded (12.9 kilometers per second (28,900 miles per hour), far exceeding the reentry speed and thermal environment of a lunar return. A spacecraft with a PICA-3 heat shield would definitely be capable of surviving Earth re-entry from a lunar trajectory. The material's high thermal tolerance and efficient ablation properties, make it well-suited for the purpose of high-speed re-entries from lunar orbit. Of course, we would need an actual demonstration of the spacecraft's heatshield's ability to successfully tolerate EDL from a lunar TEI trajectory. This is the missing capability that spawned this discussion.

Conclusion
So yes, I am contemplating using Dragon instead of Orion. The major difference is that SpaceX would need to create a variant of the trunk that functions as a service module. As for the spacecraft, it is already fine. Very little modification would be needed to the capsule, which by itself has 7x the life support of Orion. The only large scale modification needed would be to modify the empty trunk to create a service module to supply additional consumables and propulsion.

I do note in passing that all the potential space stations undergoing design or under actual development picture Dragon, Dreamchaser, Starliner or Orion as the transportation link. Starship is not included in the mix.

Note that all of this is just a thought exercise. Whether or not this would interest SpaceX is another matter.

97

SpaceX Starship Program / Re: Starship Flight 5 UPDATES : Starbase TX : NET 13 Oct 2024

« Last post by panjabi on 10/12/2024 05:04 pm »

https://twitter.com/SpaceX/status/1845146075574972633

Targeting Sunday, October 13 for Starship’s fifth flight test. A 30-minute launch window opens at 7:00 a.m. CT → http://spacex.com/launches/mission/?missionId=starship-flight-5

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SpaceX Starship Program / Re: Starship Flight 5 UPDATES : Starbase TX : NET 13 Oct 2024

« Last post by FutureSpaceTourist on 10/12/2024 05:01 pm »

https://twitter.com/bccarcounters/status/1845147269089116580

Statement of the FAA on the license:

FAA STATEMENT (Oct. 12, 2024)

The FAA has issued a license modification authorizing SpaceX to launch multiple missions of the Starship/Super Heavy vehicle on the Flight 5 mission profile. The FAA determined SpaceX met all safety, environmental and other licensing requirements for the suborbital test flight. The Flight 5 mission profile involves launch of the combined Starship/Super Heavy vehicle from Boca Chica, Texas, a return to the launch site of the Super Heavy booster rocket for a catch attempt by the launch tower, and a water landing of the Starship vehicle in the Indian Ocean west of Australia.

Edit to add:

https://twitter.com/bccarcounters/status/1845153091965833399

The @FAANews has confirmed the license includes the same mishap exceptions as flight 4.

@NASASpaceflight

"The Starship/Super Heavy Flight 5 license authorization includes the same Test Induced Damage Exceptions previously approved for Flight 4. SpaceX identified test objectives associated with certain flight events and system components of the Starship vehicle. The three approved exceptions include: failure of the thermal shield during high-heating; the flap system is unable to provide sufficient control under high dynamic pressure; and the failure of the Raptor engine system during the landing Starship burn.
There are no test induced damage exceptions related to the Super Heavy booster rocket."

FAA responding to NSF

https://twitter.com/bccarcounters/status/1845153328210018448

The @FAANews confirms the go-ahead for flight 6 as well:

@NASASpaceflight

"The SpaceX Starship/Super Heavy Flight 5 license authorization also includes FAA approval of the Flight 6 mission profile. The FAA determined the changes requested by SpaceX for Flight 6 are within the scope of what has been previously analyzed. Any modifications requested by SpaceX to the approved Flight 6 scope of operations may require further FAA evaluation. Contact SpaceX for additional detail."

FAA responding to NSF

99

Advanced Concepts / Re: Energy shield or force field made of plasma as Heatshield

« Last post by Jonathan_Blatter on 10/12/2024 04:55 pm »

I have started this topic to discuss a concept that is already a while in my mind.

Any spacecraft faces the problem of enormous heat during re-entry due to the plasma generated by the hot phase. The Chinese have now developed an energy shield that can feed from external energy like microwaves. It would be a great benefit when if, with the same principle, the hot reentry plasma could be redirected into an electrically controlled heat shield.

Is there anyone here who has some scientific know-how with handling plasma?

Energy shield or force field made of plasma according to the Tai Chi principle
[https://www.scmp.com/news/china/science/article/3247664/chinese-military-scientists-bring-energy-shield-science-fiction-life-defend-against-enemy-radiation]

This seems to me a great breakthrough, with many applications.

The Tai Chi is the principle to use the strength of the opponent and turn it against him, without using your own strength. So when you fire a laser pointer from school, it turns back at you, when using an industrial laser the field uses the power of the incoming laser energy, to feed the shield energy and turns that also against you. So even a nuclear blast gets absorbed and turned back.

Sorry, that was going to bug me... 

As mentioned, the linked paper is a defense against microwaves and not reentry plasma. But it seems the basic proposed concept is, could you have an active electromagnetic heat shield that is (due to large power requirements) somehow powered by the reentry plasma itself?

Yes That was actualy my idea.
the dificulty is to hannest the energy form the reentry plasma and somhow controll it.

100

Commercial Space Flight General / Re: Amazon Project Kuiper Broadband Constellation

« Last post by RedLineTrain on 10/12/2024 04:53 pm »

Here are some dueling investment analysts, for what it's worth -- nothing fundamental, but perhaps a whiff of investor sentiment.  Sanford C Bernstein is pessimistic.  Evercore ISI is optimistic, although it seems to be working on old information that launches would start in Q4.

Amazon is still saying "more than $10 billion" spend for Kuiper and we have seen many quotes of that.  But it will be more like $20 billion just for the first gen constellation.  Starlink currently is about $11 billion in and will happily sustain spending of $5-10 billion a year on Starlink.

Specifically addressing Kuiper he says that more than $10 billion has already been committed.

“Perhaps there’s a lesson here from Google shutting [their balloon project] Loon and Fi businesses,” said Shmulik. “In our view Kuiper has no discernible competitive advantages over operating competitors, offering Internet connectivity to rural and international users [and] offers minimal synergies with the rest of the business.”

https://advanced-television.com/2024/10/11/differing-opinions-on-project-kuiper/