19 votes
Accepted

Why was the Atlas V's SRB kept attached for 1 minute after burnout in the OFT-2 mission?

The solid rocket boosters are left attached because they don't want to separate them during the phase of highest dynamic loading of the vehicle. The risk of something going wrong during this critical ...
TrySCE2AUX's user avatar
  • 3,255
16 votes

On large diameter Atlas V fairings, why is the Centaur inside the fairing?

A document from NASA Safety & Mission Assurance suggests the reason is structural: Thin-­skinned Centaur cannot easily support the giant 5.4 meter diameter payload fairing, so the Contraves ...
Russell Borogove's user avatar
15 votes
Accepted

Why do the shapes of these two exhaust plumes from an Atlas V 411 look different?

Yes, the pressure of the first stage exhaust is always at least slightly subatmospheric, because that gives the maximum average ISP over the whole burn time. Rockets with boosters attached (parallel ...
Rikki-Tikki-Tavi's user avatar
13 votes
Accepted

How does Atlas V maintain stable flight with asymmetric solid rocket boosters?

The nozzles of the SRBs are canted outward, so the line of thrust from each SRB passes close to the center of mass of the rocket, so that the net torque from asymmetrical booster arrangements is ...
Russell Borogove's user avatar
11 votes
Accepted

Why are some rockets orange?

From perusing online, it seems there's a consensus that the insulating foam is just that color. They painted the Delta II, but stopped painting due to the added weight. As to why they painted the ...
Arthur Dent's user avatar
  • 1,135
10 votes
Accepted

InSight Launch - Centaur Fuel Rich

Centaur upper stages have a Propellant Utilization (PU) system. While this document is old, the fundamentals apply. To realize optimum performance in a liquid-fueled bipropellant space ...
Organic Marble's user avatar
10 votes
Accepted

What is the meaning of "BODA"?

BODA appears to stand for "burn-out detection algorithm". During the launch of an Atlas V equipped with solid rocket boosters, the main engine throttles down after about 75 seconds to limit g-force. ...
Russell Borogove's user avatar
9 votes
Accepted

What are the advantages of Delta IV over Atlas V

Since 2004, it's been policy of the US government to assure there are at least two launcher families available for launching "national security payloads" (e.g. military surveillance and communication ...
Russell Borogove's user avatar
9 votes

How does Atlas V maintain stable flight with asymmetric solid rocket boosters?

There are tradeoffs at work here. The current configuration allows them to use one first stage design for 1-5 boosters. A first stage that has symmetric attachment points, needs 2+4+4 = 10 attachment ...
Hobbes's user avatar
  • 128k
7 votes
Accepted

ULA just launched a very asymmetric Atlas V 511. Why does its plume look so asymmetric... after SRB jettison?

Looking at the engine configurations for the Atlas V: Credit: ULA, from Spaceflight Now article I think it's likely a plume impingement effect from the two nozzles of the RD-180 engine. The plume ...
BrendanLuke15's user avatar
7 votes
Accepted

Why was OSIRIS-REx almost destroyed because of a loss of pressure following the SpaceX "fast fire"?

SLC-40 and 41 are neighbors, no other pads in between. Some debris landed further away than SLC-41. They share some systems, e.g. the deluge system. The only good source I've found is this post by a ...
Hobbes's user avatar
  • 128k
6 votes
Accepted

Is it feasible to launch NASA's InSight mission Mars using a Falcon 9, instead of an Atlas V rocket?

Yes, however the decision to launch the mission on Atlas V was made years ago, and it is impossible to change now that the launch is less than a month away. InSight is estimated to weigh 360 kg. ...
T.J. Tarazevits's user avatar
6 votes

Why can't Falcon Heavy accelerate deep space payloads as fast as Atlas V and Delta Heavy?

The short answer is that the Isp of the Falcon's RP-1/LOX upper stage engines is much less than the Atlas V's LH/LOX. The primary metric of interest is $\Delta v$, which depends on $I_{sp}$ and mass ...
RickNZ's user avatar
  • 556
5 votes

Why was OSIRIS-REx almost destroyed because of a loss of pressure following the SpaceX "fast fire"?

Satellites are finely tuned to work in a specific environment. Space is a tough environment, but usually pretty consistent. One of the things required is to keep the spacecraft at a certain operating ...
PearsonArtPhoto's user avatar
  • 121k
5 votes

How does Atlas V maintain stable flight with asymmetric solid rocket boosters?

The Delta rocket started out with separate versions of the aft end for different numbers solid rocket boosters attached. Eventually McDonnell Douglas standardized, introducing the Universal Boattail ...
M McReynolds's user avatar
5 votes

What is the source of the 'whoop' sound made before the liftoff (T-3s) of Atlas-V rocket?

If it's a rocket launch, happens at around engine ignition, and it sounds like some variation of 'whooop', you can bet it's the sound of turbomachinery very rapidly spooling up. Consider those ...
Rune's user avatar
  • 51
4 votes

What happened to the Atlas IV?

I did some searching. Russell's comment provides the only theory I've found: LM had Atlas III and Titan IV. Atlas V as a follow on to both and since it incorporated elements of each, so did the name....
Hobbes's user avatar
  • 128k
3 votes
Accepted

What is the Oxidiser/Fuel Ratio of the Atlas V Centaur Upper Stage?

Since we know the Centaur on Atlas 5 uses RL10C engines, we can look that up. The current RL10C engine mixture ratio is 5.5.
Organic Marble's user avatar
3 votes

How much will Europa Clipper weigh?

An estimate from 2016 has the mass budget at 5000 kg. Curt Niebur, outer planets program scientist at NASA Headquarters, said at the meeting that the biggest challenge of adding the lander to the ...
Hobbes's user avatar
  • 128k
2 votes

What are these 'Lego' plates inside the Atlas 5 fairing?

As detailed in this other answer, they provide noise dampening. Thanks to Hobbes who is possibly a Helmholtz nut. ;) (...gotta wait 2 days before I can close this question...)
KlaymenDK's user avatar
  • 153
1 vote
Accepted

Does RUAG Space recover and reuse Ariane 5 and Atlas V payload fairings after splashdown?

No, they don't. Here is the RUAG Space page for fairings: https://www.ruag.com/en/products-services/space/launchers/launchers As we can see, no mention of reusability. Also no mentions it's planned in ...
Heopps's user avatar
  • 9,071
1 vote

How much will Europa Clipper weigh?

According to Wikipedia Europa Clipper: Launch mass 6,000 kg (13,200 lb) Dry mass 2,616 kg (5,767 lb) (without science payload) Payload mass 352 kg (776 lb) So the probe itself weighs 352 kg (...
LoveForChrist's user avatar
1 vote

What's the thickness and weight of rocket tanks?

For ariane 5 the thickness is: 8mm for the solid boosters 4mm for the cryogenic main stage. However both have an additional thermal insulation layer. I couldn't find data for the booster [see ...
Antzi's user avatar
  • 12.6k

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