|
Estimation of the
terminal
velocity (dV)
[dV = Isp [Ns/kg] * ln (Mf/Me)]
1. -- Mf - first stage: Total mass of
the launcher
Me - first stage: Empty mass of the first
stage +total mass of the second stage +fairing +payload
2. -- Mf - second stage: Total mass of the second stage with payload
Me - second stage: Empty mass of the
second stage with payload
| |
vac Isp (sec) |
=Ns/kg |
Mf (kg) |
Me (kg) |
Mf/Me |
ln Mf/Me |
Isp * ln (Mf/Me) |
|
1st |
281.5 |
2760 |
84,832 |
21,792 |
3.893 |
1.35913
|
3,751
|
| |
|
|
|
|
|
|
|
|
2nd |
290 |
2844 |
9,004
|
1,534
|
5.870
|
1.76979
|
5,033
|
| |
|
|
|
|
|
dV Total*
|
8,794 [m/sec]
|
* dV
(vacuum); without losses of about 20% of velocity
Therefore is the real dV nearby 7,028
m/sec for payload 100
kg, and is not enough
Estimation of the
terminal
velocity (dV) with longer second stage and third stage
[dV = Isp [Ns/kg] * ln (Mf/Me)]
1. -- Mf - first stage: Total mass of
the launcher
Me - first stage: Empty mass of the first
stage +total mass of the second stage +KM +fairing +payload
2. -- Mf - second stage: Total mass of the second stage +KM +payload
Me - second stage: Empty mass of the
second stage +KM +payload
3. -- Mf - third stage: Total mass of the KM with payload
Me - third stage: Empty mass of the KM
with payload
| |
vac Isp (sec) |
=Ns/kg |
Mf (kg) |
Me (kg) |
Mf/Me |
ln Mf/Me |
Isp * ln (Mf/Me) |
|
1st |
281.5 |
2760 |
85,783 |
22,743 |
3.772 |
1.32758
|
3,664
|
| |
|
|
|
|
|
|
|
|
2nd |
290 |
2844 |
10,135
|
2,135
|
4.748
|
1.55771
|
4,430
|
| |
|
|
|
|
|
|
|
|
Saman-1 |
286.5 |
2810 |
415
|
230
|
1.806
|
0.59117
|
1,661
|
| |
|
|
|
|
|
dV Total*
|
9,755 [m/sec]
|
* dV
(vacuum); without losses of about 20% of velocity
Therefore is the real dV nearby 7,804
m/sec for payload 100 kg
|