The Falcon 9 first stage is making two or three burns for descending:
- boostback burn (optional, depends on return to launch site vs ocean landing)
- entry burn
- landing burn
But how many burns is the New Shepard doing?
The Falcon 9 first stage is making two or three burns for descending:
But how many burns is the New Shepard doing?
The Falcon 9 first stage is making three burns wile descending:
Nope. It is making two burns while descending.
- boostback burn
- descent burn
This is called the entry burn.
Its purpose is two-fold:
Note that this might technically count as two burns, depending on how you define the term:
But how many burns is the New Shepard doing?
One. It doesn't need to "boost back", because it never went anywhere in the first place, it is just going straight up. And it doesn't need the entry burn because it is never going nearly as fast as a Falcon 9. Again, it never goes anywhere near orbit, it just barely coasts up to the Kármán line and falls down again.
Its maximum velocity on ascent is 1000 m∕s, on descent, it never goes past 1165 m∕s and at engine relight, it has slowed down to a measly 165 m∕s using only aerodynamic drag. [All numbers from the official webcast of NS-13.]
In comparison, the Falcon 9 first stage booster goes up to well over 2150 m∕s on ascent, and roughly 2200 m∕s on descent, which is when it fires the entry burn and slows down to ~1200 m∕s. The landing burn is fired at ~190 m∕s. [All numbers from the Flight Club simulation of Starlink L-15.]
In other words, New Shepard never even reaches the velocity that F9 has after slowing down using the entry burn.
New Shepard does most of its deceleration using its aerodynamic devices. In particular, if you watch the velocity during one of their webcasts, deploying the drag brake is almost as if they were pulling the handbrake at highway speeds.
Only one burn, just before landing, according to Blue Origin's broadcast of NS-12's flight. The only events during climb relating to engines are liftoff and MECO (main engine cut off). After apogee, 45:00 in the video, T+4:45, the only events at all are wedge fins deploy, drag brake deploy, booster restart, and booster touchdown.
(Here are photos and discussion of its wedge fins and drag brakes.)
Displayed telemetry of the descending booster's speed, and a lack of visible exhaust plume despite seeing plenty of detail of the booster itself, confirm that no other burns happened during descent.
Falcon 9 might also have needed only one burn while descending, had it ever flown roughly straight up and down instead of pushing a payload sideways into orbit.