Vehicle Exit From Sled Into Orbit

At the end of the acceleration run, the vehicle stops accelerating, separates from the sled, and enters a departure orbit, while the sled continues to accelerate at 3 gees until it reaches the top of the loop.

Vehicle acceleration does not end abruptly from 3 gees; the horizontal acceleration reduces smoothly from 3 gees to zero gees over one second, a "jerk" of 30 m/s³. If the vehicle and sled are moving faster than orbital velocity, there will be some upwards acceleration force as well, which is relieved towards the end of the "jerk", stretching the "one second" deployment time a little; 52 msec for a one gee upwards deployment force at escape velocity.

The vehicle rides behind the sled heat shield throughout the 6 minute (LEO) to 8 minute (escape) acceleration run. After release, the vehicle will spend a minute???? (LEO) to 30 seconds (escape) punching through most of the remaining atmosphere.

A table of vehicle acceleration and sled-relative position:

inertial
acceleration

sled-relative

velocity

displacement

ax

ay

a

time

vx

vy

x

y

m/s²

m/s²

m/s²

sec

m/s

m/s

meters

meters

30.0

10.0

31.6

0.000

0.0

0.0

0.00

0.00

25.0

10.0

26.9

0.157

-0.4

0.0

-0.02

0.00

20.0

10.0

22.4

0.309

-1.5

0.0

-0.16

0.00

15.0

10.0

18.0

0.453

-3.3

0.0

-0.50

0.00

10.0

10.0

14.1

0.583

-5.6

0.0

-1.07

0.00

5.0

5.0

7.1

0.818

-10.9

0.6

-2.99

0.05

0.0

0.0

0.0

1.054

-17.4

2.4

-6.30

0.37

SledRelease.ods . . . LibreOffice Calc attachment


Sled Deploying from vehicle

The drawing is not to scale, and the nose angle may be more slender.

SledAndVehicleExit.png

SledAndVehicleExit.png, 2250 pixel wide image . . . . . . SledAndVehicleExit750.png, 750 pixel wide image . . . . .

SledAndVehicleExit.odg, LibreOffice draw original


Climb-out Time, Atmosphere Density Encountered

LEO400

M288

GTO

constr1

const2

const7

moon

apogee target

km

6778

14420

42164

75950

125485

270067

384399

launch velocity

km/s

7.4832

8.7659

9.8769

10.1964

10.3651

10.5097

10.5480

launch velocity

mach

26.26

30.76

34.66

35.78

36.37

36.88

37.01

exit air density

kg/m3

4.3E-5

3.0E-5

2.3E-5

2.2E-5

2.0E-5

2.0E-5

2.0E-5

power/area flat

MW/m2

9.02

10.09

11.25

11.45

11.12

11.59

11.72

power/area cone

MW/m2

1.05

1.18

1.32

1.34

1.30

1.36

1.37

20° cone

exit air mass

kg/m2

28.05

5.15

1.24

0.64

0.36

0.21

0.17

energy/area flat

MJ/m2

785

198

60.5

33.0

19.5

11.5

9.7

energy/area cone

MJ/m2

31.4

7.9

2.42

1.32

0.78

0.46

0.39

20° cone

SledVehicleExit (last edited 2020-11-04 21:45:24 by KeithLofstrom)