51 votes
Accepted

Why isn't SpaceX constructing the Super Heavy launch mount on top of the water?

Salt does all sorts of unpleasant things to just about every building material humans use. Hot salt spray, such as you'd get from a rocket launch, is even worse: spraying something with hot saltwater ...
Mark's user avatar
  • 15.3k
48 votes
Accepted

Will the Falcon Heavy be far enough in 12 seconds to not cause damage?

Not even close. In fact, at 12 seconds in, you're looking at maximum damage to not just the pad itself, but the surrounding area as well. You're going to have tons of debris (most of it burning and ...
Machavity's user avatar
  • 7,905
44 votes

Why do Crew Dragon astronauts need to climb up one level using the stairs before ingress?

Scott Manley of the YouTube has a great video that addresses the extra level of the tower, located at the seven minute mark of a recent posting. Verbatim transcript from the video: So pad 39A is ...
fred_dot_u's user avatar
  • 1,935
34 votes
Accepted

Why does the CRS-8 Falcon 9 rocket appear to be swaying before launch?

Because it is. It is a very tall structure, first stage alone is 140 feet, plus second stage, plus fairing. It is considered at the limit of how tall and thin they can make it. Wikipedia says the ...
geoffc's user avatar
  • 79.5k
26 votes

What kept crosswinds from pushing Apollo rockets into their own gantry?

The clearances were calculated to be OK up to a 95th percentile wind. I assume there was a Launch Commit Criteria (LCC) for the ground wind, but I have not been able to find an Apollo LCC document. ...
Organic Marble's user avatar
19 votes

What exactly is the purpose of connection links strapped between the rocket and the launch pad

In general, umbilicals are provided from the launch pad to the vehicle for any services that need to be provided after the vehicle is installed on the launch mount, and to remove hazardous gases from ...
Organic Marble's user avatar
17 votes
Accepted

How can a rocket go straight up after ignition?

Rockets can use different systems for attitude control (control thrusters, fins, gyroscopes, TVC, ...). Since you ask for the seconds after liftoff, the relevant system is TVC (Thrust Vector Control). ...
DaGroove's user avatar
  • 1,334
16 votes

What controls hold-down clamp release: rocket... or ground control?

For shuttle it was commanded by the vehicle computers. At T-31 seconds control of most remaining countdown events was handed over to the vehicle, including SRB ignition and blowing the hold-down post ...
Organic Marble's user avatar
14 votes
Accepted

Were launchpads at KSC built with pilings or footings?

Based on this article, 39A is just concrete on top of sand. That does seem a little ridiculous though. The pumps piled up another portion of the dredged sand on the launch pad, creating a flat-...
Ash Pera's user avatar
  • 156
14 votes
Accepted

What controls hold-down clamp release: rocket... or ground control?

For Apollo, the signal came from a small computer room built inside the mobile launch platform. Giant holddown arms, whose name exactly describes their function, are positioned on the launcher ...
DrSheldon's user avatar
  • 47.9k
14 votes
Accepted

Does the SLS mobile launch platform share any hardware with STS or even Saturn I/V MLP?

The two-story gray platforms at the base were originally built for Apollo, modded for shuttle, and now modded again for SLS. The towers are new and suffered a lot of cost and schedule issues. Most of ...
Organic Marble's user avatar
13 votes

What holds the Space Shuttle orbiter itself stable on the launch pad?

The only hold-downs are the eight SRB bolts. This leads to the "Shuttle twang" when the main engines start. They're pushing to one side of the SRB hold downs, so they bend the stack just a bit. ...
Bob Jacobsen's user avatar
  • 12.7k
13 votes

Why would someone need vertical loading for a SpaceX rocket?

I didn't dig too hard for sources because this is probably a very minor expansion on top of the other answers, but WHICH payloads might require vertical integration? Ones with big stinking mirrors ...
Erin Anne's user avatar
  • 11.2k
12 votes

Will the Falcon Heavy be far enough in 12 seconds to not cause damage?

To avoid damage to the pad, the rocket must have traveled down range far enough that if it exploded, the debris would not land back on the pad. The issue isn't height, it's horizontal distance. 12 ...
Byron Jones's user avatar
12 votes
Accepted

How are umbilical connectors held in place until their intended detachment?

This paper surveys a large number of umbilical designs. For the mechanical connections to the vehicle, it lists two types of detachable locking devices. The type of locking mechanism ...
Organic Marble's user avatar
12 votes

Why isn't SpaceX constructing the Super Heavy launch mount on top of the water?

Environmental impact may be a major consideration The effect on the local water environment from that sort of blast into it could be severe and far reaching in the neighborhood around a water based ...
Michael Durrant's user avatar
11 votes

Was LC39A built with a rocket much larger than the Saturn V in mind?

Launch Pads 39A and 39B were initially built for either the Saturn C-8 or the Nova rockets, each of which has a lift off thrust of about 7000 tons, about twice that of the Saturn V. These were ...
PearsonArtPhoto's user avatar
  • 121k
11 votes

What pushes back on rockets?

Newton's Third Law states that if object A pushes on object B with a certain amount and direction of force then object B pushes on object A with same amount and opposite direction of force. Notice ...
DrSheldon's user avatar
  • 47.9k
10 votes
Accepted

Does SpaceX plan to repair SLC-40?

On the prelaunch press conference about LC-39A Gwynne Shotwell (SpaceX COO) said that they plan on repairing the SLC-40 pad now, hoping to finish it in summer. Youtube: NASA Holds Pre-launch Briefing ...
jkavalik's user avatar
  • 5,128
10 votes
Accepted

What holds the Space Shuttle orbiter itself stable on the launch pad?

Prior to launch the Orbiter was mounted on the External Tank and the External Tank was mounted to the Solid Rocket Boosters. The entire assemblage was referred to as "the stack". The entire weight ...
Organic Marble's user avatar
10 votes

What happens to the acoustic energy removed by a sound suppression system?

Yes, the water heats up. Lots of it evaporates. There is a system to catch and filter the remainder, which is polluted with combustion products of the SRBs. Those massive clouds in the foreground are ...
Hobbes's user avatar
  • 128k
10 votes
Accepted

Were all three Mobile Launch Platforms ever in use simultaneously?

In August 1990, there were three shuttle stacks at least partially assembled on their MLPs at the same time: Columbia for STS-35, Atlantis for STS-38 and Discovery for STS-41. The picture in this ...
Nimloth's user avatar
  • 331
9 votes
Accepted

What is the utility of this peanut-shaped ground facility?

Apparently it is an overhead tank (OHT) associated with fire suppression system of Second Launch Pad in Sriharikota. Learned about this from a recent tender about upgrading fire suppression to meet ...
Ohsin's user avatar
  • 1,812
9 votes
Accepted

Size of the new Starship Launch tower at Boca Chica?

The pier is just shy of 3 pickups in width as you can see in the photo below from RGV Aerial. The overall length of a Chevrolet Silverado pickup truck 4x2 double cab with 6.6-foot box is 231.8 inches. ...
D_Bester's user avatar
  • 653
9 votes

Location of crawler/transporter during launch

The Crawler Transporters are removed once the mobile launch platform is seated on the pad structure. The mobile Launch Platforms have holes in them allowing rocket exhaust through to the flame trench ...
GremlinWranger's user avatar
8 votes
Accepted

How much water to the east is needed?

This depends on the rocket you're launching. The first stage usually lands a few hundred km away from the launch point. Here is an example of the exclusion zones for a SpaceX Falcon 9 launch. The red ...
Hobbes's user avatar
  • 128k
8 votes

Why do KSC crawler-transporters use caterpillar treads instead of rail tracks?

The Kennedy Space Center Story, written by NASA in June 1970, NTRS document 19710024295, p. 29 describes the options that were considered, and the reason for the final choice: The scheme by which ...
DrSheldon's user avatar
  • 47.9k
8 votes
Accepted

What is happening to the rocket in this ISRO photo - what are these huge platforms?

Those platforms are access walkways for technicians, used for the final inspection of the rocket before launch. The platforms are positioned around the rocket for inspection, then rotated out of the ...
Hobbes's user avatar
  • 128k
8 votes
Accepted

Seeing the ground from the shuttle before launch?

This is a frame from a video I shot in the Shuttle Mission Simulator back in the 90s. I was sitting in the commander's seat. The shoebox with the red stripes is supposed to be the launch tower, you ...
Organic Marble's user avatar

Only top scored, non community-wiki answers of a minimum length are eligible