Answer · confidence: partial
Why do spacecraft need two pushes instead of one long push?
Research question: What does a two-burn transfer look like to an ordinary passenger, and why does the spacecraft need a second burn at the far end instead of one long push?
The records show that a Hohmann transfer uses an elliptical transfer orbit that touches both the starting and target circular orbits tangentially, with a propulsive kick needed at each tangent point 73. The spacecraft gets a first thrust impulse to enter the transfer ellipse and a second at the far intersection to circle the target body 9. The Hohmann transfer is the optimal two-impulse coplanar transfer between two circular orbits, which is why it uses exactly two burns rather than a single long push 15. The records describe a transfer orbit only as an intermediate elliptical orbit 1 and say nothing about what a passenger would see or feel during the burns, so that part of the question is not answered. The newest fact is from 2018, roughly eight years before October 2026 15.
Checked 2026-10-21. Only documented and supported facts are used.
Dig deeper on this questionSources
[1] supported
A transfer orbit is an intermediate elliptical orbit used to move a spacecraft from one circular, or largely circular, orbit to another.
"In orbital mechanics , a transfer orbit is an intermediate elliptical orbit that is used to move a spacecraft in an orbital maneuver from one circular , or largely circular, orbit to another."Transfer orbit
[2] supported
A Hohmann transfer is an orbital maneuver that moves a spacecraft from one circular orbit to another using two engine impulses.
"An orbital maneuver that moves a spacecraft from one circular orbit to another using two engine impulses"List of orbits
[3] supported
A Hohmann transfer orbit is an elliptical orbit used to transfer a spacecraft between two circular orbits of different altitudes in the same plane.
"Hohmann transfer orbit , an elliptical orbit used to transfer a spacecraft between two circular orbits of different altitudes in the same plane"Transfer orbit
[4] supported
The Hohmann transfer maneuver is named after Walter Hohmann.
"This maneuver was named after Walter Hohmann"List of orbits
[5] supported
A bi-elliptic transfer is a slower method of transfer that may be more efficient than a Hohmann transfer orbit.
"Bi-elliptic transfer , a slower method of transfer, but one that may be more efficient than a Hohmann transfer orbit"Transfer orbit
[6] supported
A geostationary transfer orbit is an elliptic orbit whose perigee is at the altitude of a low Earth orbit and whose apogee is at the altitude of a geostationary orbit.
"An elliptic orbit where the perigee is at the altitude of a low Earth orbit (LEO) and the apogee at the altitude of a geostationary orbit"List of orbits
[7] supported
The Hohmann transfer ellipse touches both the starting orbit and the target orbit tangentially, and a propulsive kick is needed at each of those tangent points to match the orbital speed.
"Die Transfer- Ellipse ( Hohmann-Bahn ) verläuft sowohl zur Ausgangsbahn als auch zur Zielbahn tangential; dort ist jeweils ein Kraftstoß nötig, um die Geschwindigkeit anzupassen."Hohmann-Transfer
[8] supported
The transfer requires exactly two impulses or speed changes, one at departure and one at arrival.
"sind zwei Impulsstöße bzw. zwei Geschwindigkeitsänderungen"Hohmann-Transfer
[9] supported
In the Mars example, the spacecraft gets a thrust impulse at the first intersection to enter the transfer ellipse, and a second thrust impulse at the far intersection to circle Mars.
"wechselt dann am in der Abbildung unteren Schnittpunkt (von 1 mit 2) durch einen Schubimpuls zum Transfer via der elliptischen Hohmann-Bahn (gelbe Transferbahn 2), bis sie am in der Abbildung oberen Schnittpunkt (von 2 mit 3) den Mars erreicht, um durch einen weiteren Schubimpuls nun diesen zu umkreisen"Hohmann-Transfer
[10] supported
Walter Hohmann in 1925 regarded this transfer as optimal, but for very large radius ratios or inclined or counter-rotating orbits a bi-elliptic transfer is more energy-efficient.
"1925 wurde dieser Transfer von Walter Hohmann als optimal angesehen. [ 1 ] Für koplanare , kreisförmige Ausgangs- und Zielbahnen mit einem Radiusverhältnis unter 11,94 ist er das auch, für extremere Verhältnisse und stark gegeneinander geneigte oder gar gegenläufige Bahnen ist ein bi-elliptischer Transfer energetisch günstiger."Hohmann-Transfer
[11] supported
In a geostationary transfer orbit, the satellite itself usually raises the perigee by firing a rocket motor at the apogee.
"Das Perigäum wird in den meisten Fällen vom Satelliten selbst angehoben, indem im Apogäum ein Raketenmotor gezündet wird."Satellitenorbit
[12] supported
The paper applies directly to cases where a two-impulse transfer is the optimal solution, meaning the spacecraft's optimal path uses two thrust pulses rather than one.
"It applies directly to cases in which a two-impulse transfer is the optimal solution and presents the results as functions of the corresponding idealized Hohmann transfers."Optimal impulsive transfers between real planetary orbits (1975)
[13] supported
The geostationary transfer orbit is an intermediate orbit used to reach geostationary orbit, and the document links it to the Hohmann transfer.
"Übergangsorbit, um einen GEO zu erreichen (siehe auch Hohmann-Transfer )."Satellitenorbit
[14] supported
In the Hohmann transfer, the spacecraft starts on the initial orbit, travels along the transfer orbit to a second pulse point, and then continues along the final circular orbit to the terminal point, so the second burn occurs where the transfer ellipse meets the target circle.
"spacecraftstartsfromtheinitialpointontheinitialorbit,movesclockwisealongthetransferorbituntilthesecondpulse"Hohmann transfer via constrained optimization (2018)
[15] supported
The Hohmann transfer is the optimal two-impulse coplanar transfer between two circular orbits, which is why it uses exactly two burns rather than a single long push.
"Herebythe globaloptimality,wemeanthattheHohmanntransferisoptimumamongallpossibletwo-impulsecoplanartransfers."Hohmann transfer via constrained optimization (2018)
[16] supported
When the spacecraft is to enter an intermediate orbit at apogee, a second high-thrust impulse is required to achieve that orbit.
"In the case where the spacecraft enters an intermediate orbit at the apogee, a second high-thrust impulse is used to achieve this."Novel numerical optimisation of the Hohmann Spiral Transfer (2013)