Did Apollo have braking rockets for soft landing on Earth? I have checked Google but cannot find an answer.
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1$\begingroup$ Although the Apollo doesn't have breaking rockets for landing, some spacecraft, like the Soyuz do: en.wikipedia.org/wiki/Soyuz_(spacecraft) $\endgroup$– SE - stop firing the good guysSep 27, 2020 at 9:10
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$\begingroup$ for other spacecraft beside Apollo, see How does a gamma ray altimeter work? What kind of sensor is used? and Soyuz landing ground detection and How does New Shepard Crew Capsule sense proximity to trigger retropropulsion just before impact? and When did soviet capsules begin using retropropulsion immediately before landing? $\endgroup$– uhohSep 27, 2020 at 9:25
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1$\begingroup$ and SpaceX and propulsive landing on Mars — what just happened? (and why?) $\endgroup$– uhohSep 27, 2020 at 9:26
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3 Answers
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No, the Apollo Command Module (the part that made it back to Earth) did not have braking rockets. Instead, it had several parachutes and landed in the water.
The descent was first slowed by two drogue chutes. These deployed at about 7 km above sea level and slowed the spacecraft down enough so the three main chutes could be deployed at about 3 km. These bigger chutes then slowed the spacecraft down for safe landing in the water.
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7$\begingroup$ Soyuz has both parachutes and breaking rockets. Apollo water impact was not soft, about 12 to 40 g. $\endgroup$– UweSep 27, 2020 at 9:33
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12$\begingroup$ @Uwe: One hopes that the Soyuz doesn't have breaking rockets, but that they don't break and so brake the capsule to a survivable landing. $\endgroup$– jamesqfSep 28, 2020 at 4:48
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6$\begingroup$ @jamesqf Both the U.S. and the Soviets did have a lot of breaking rockets over the years, though. Indeed, pretty much the whole Soviet lunar program had breaking rockets. $\endgroup$– reirabSep 28, 2020 at 17:23
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2$\begingroup$ @reirab: Sure, but we were discussing the Soyuz landing rockets specifically, and I can't find any report of them breaking in a quick search. A couple of the Soyuz launch vehicles did break, though. $\endgroup$– jamesqfSep 29, 2020 at 3:31
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2$\begingroup$ @RolandPihlakas Yes, you are missing that my comment was also a joke. :) My link for "breaking rockets" was the Soviet N-1, of which all four flights resulted in rather violent disintegration of the stack. One of them took out the entire launch complex. $\endgroup$– reirabOct 27, 2020 at 18:56
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No it didn't, Apollo was designed with a parachute assisted water landing in mind. However there was one contingency for which considerations for a hard landing (landing on the ground with parachutes instead of the water) were made.
During the launch the Apollo spacecraft went through several stages and during each one there was an abort plan. For the most of the launch until they reached space the primary means of aborting used a thin solid rocket booster attached above the capsule (the escape tower) to quickly pull it away from the main booster rocket where it could deploy chutes and make a landing.
Since Apollo launched eastward from Cape Canaveral they would normally abort into the Atlantic Ocean. For a pad abort the angled rocket was designed to pull the capsule east as well so it would be over the water. However a strong wind could risk pushing it back inland. Since this was a marginal scenario no extra weight was spared to equip Apollo with Soyuz style braking rockets. Instead extra work was put into the crash couches to make the landing survivable, although it was projected that at least one of the three astronauts would suffer non-life threatening injuries from the impact if such an escape had to be made.
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For lunar flights, the Apollo command and service module did not require retrorockets to return the command module to Earth, as the flight path took the module through the atmosphere, using atmospheric drag to reduce velocity.
Retrorockets were used to back the S-IC and S-II stages off from the rest of the vehicle after their respective shutdowns during the Saturn V's launch to Earth parking orbit.
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3$\begingroup$ The question was about the very last phase of Earth landing, just before contact with the surface. $\endgroup$– UweSep 28, 2020 at 14:13
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1$\begingroup$ @Uwe i think this answer is valid for last phase of landing $\endgroup$– AminMSep 29, 2020 at 4:41
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4$\begingroup$ During the very last phase of Earth landing, there was no service module and no stages of the Saturn V. $\endgroup$– UweSep 29, 2020 at 8:51