After 100 days of 7g acceleration, a vessel travels total distance of 9,842 AUs (.155 Light Year, LY). It gained velocity of about 150 AU/day (.866 c, 86.6% light speed).
Assume 7G vessel cruises at this velocity until the optimal time/distance to start decelerating at 7g. |
Decel.
Time(t) | Spot
Velocity (Vt) | Spot
Distance (dt) | Daily
Dist. (dΔ) | 7G
Dist.(d7G) | Total
Fuel (F) |
0 days | 149.93 AU/dy | 86.59% c | 9,811.1 AU | 0.1551 LY | 0.0 AU | 9,811.1 AU | 27.974% GW0 |
1 days | 149.46 AU/dy | 86.32% c | 9,661.7 AU | 0.1528 LY | 149.4 AU | 9,960.5 AU | 28.210% GW0 |
2 days | 148.98 AU/dy | 86.04% c | 9,512.8 AU | 0.1504 LY | 148.9 AU | 10,109.4 AU | 28.445% GW0 |
3 days | 148.48 AU/dy | 85.76% c | 9,364.4 AU | 0.1481 LY | 148.4 AU | 10,257.9 AU | 28.679% GW0 |
4 days | 147.98 AU/dy | 85.46% c | 9,216.5 AU | 0.1457 LY | 147.9 AU | 10,405.8 AU | 28.913% GW0 |
5 days | 147.46 AU/dy | 85.17% c | 9,069.1 AU | 0.1434 LY | 147.4 AU | 10,553.2 AU | 29.146% GW0 |
6 days | 146.94 AU/dy | 84.86% c | 8,922.2 AU | 0.1411 LY | 146.9 AU | 10,700.1 AU | 29.378% GW0 |
Given |
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| dt-1 - dt | dΔ + ΣdΔ | 1-(1-ε∇)100+t |
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For success, the 7G resupply vessel must slow down to match the 1G vessel's cruise velocity (.644c = 111.5 AU/day). This table describes daily progress throughout the 48¼ days of 7G deceleration. |
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Interstellar 1G Vessel
starts its one year of acceleration at day 0.
After this year, vessel stops acceleration and cruises at 111.5 Astronomical Units per day (.644 c).
One year of 1G acceleration has taken vessel to 23,841 AUs, .377 Light Year (LY).
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Interstellar 7G Snowball
In this example, 7G snowball (traditional habitat encased in large volume of ice) starts its 100 day acceleration at day 260 of 1G vessel’s acceleration.
On day 360, 7G vessel stops propulsion, and cruises at 149.9 AUs per day (.865c).
100 days of 7G acceleration takes vessel to 9,842 AU, (= .155 LY). |
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Decel.
Time(t) | Spot
Velocity (Vt) | Spot
Distance (dt) | Daily
Dist. (dΔ) | 7G
Dist.(d7G) | Total
Fuel (F) |
7 days | 146.40 AU/dy | 84.56% c | 8,775.8 AU | 0.1388 LY | 146.4 AU | 10,846.5 AU | 29.609% GW0 |
8 days | 145.86 AU/dy | 84.24% c | 8,630.0 AU | 0.1365 LY | 145.8 AU | 10,992.3 AU | 29.840% GW0 |
9 days | 145.30 AU/dy | 83.92% c | 8,484.7 AU | 0.1342 LY | 145.3 AU | 11,137.6 AU | 30.070% GW0 |
10 days | 144.73 AU/dy | 83.59% c | 8,340.0 AU | 0.1319 LY | 144.7 AU | 11,282.3 AU | 30.299% GW0 |
11 days | 144.15 AU/dy | 83.26% c | 8,195.8 AU | 0.1296 LY | 144.1 AU | 11,426.4 AU | 30.527% GW0 |
12 days | 143.56 AU/dy | 82.91% c | 8,052.3 AU | 0.1273 LY | 143.6 AU | 11,570.0 AU | 30.755% GW0 |
Given |
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| dt-1 - dt | dΔ + ΣdΔ | 1-(1-ε∇)100+t |
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Points ⓐ thru ⓕ map out following events:
ⓐ After 360 days, resupply vessel ends 100 days of 7G propulsion and starts cruise at 149.9 AU/day.
ⓑ After 365¼ days of 1G acceleration, primary vessel cruises at 111.5 AU/day.
ⓒ After 400 days (about 35 days of constant velocity), resupply vessel is about 12,000 AU behind primary vessel.
ⓓ After 500 days (about 135 days of constant velocity),, resupply vessel closes the gap to slightly over 8,000 AU.
ⓔ 600 days (100 more days of constant velocity), gap closes even more to just over 4,000 AU.
ⓕ 684 days, gap shrinks to about 1,000 AU in prep for 7G vessel’s deceleration duration of 48¼ days needed to match speed of primary vessel.
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Describe primary vessel’s cruise distance by linear equation:
d = 111.5 t - 16,884 AU
Resupply vessel’s cruise distance:
d= 149.9 t - 44,152 AU
By inspection, we expect a pending intercept of these two cruise tracks about one LY and two years from start of primary vessel’s track. HOWEVER, the resupply vessel track must become nonlinear at about 684 days for 48¼ day deceleration maneuver.
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Decel.
Time(t) | Spot
Velocity (Vt) | Spot
Distance (dt) | Daily
Dist. (dΔ) | 7G
Dist.(d7G) | Total
Fuel (F) |
13 days | 142.96 AU/dy | 82.57% c | 7,909.3 AU | 0.1251 LY | 143.0 AU | 11,712.9 AU | 30.982% GW0 |
14 days | 142.34 AU/dy | 82.21% c | 7,767.0 AU | 0.1228 LY | 142.3 AU | 11,855.3 AU | 31.208% GW0 |
15 days | 141.72 AU/dy | 81.85% c | 7,625.3 AU | 0.1206 LY | 141.7 AU | 11,997.0 AU | 31.433% GW0 |
16 days | 141.08 AU/dy | 81.48% c | 7,484.2 AU | 0.1183 LY | 141.1 AU | 12,138.1 AU | 31.658% GW0 |
17 days | 140.42 AU/dy | 81.10% c | 7,343.7 AU | 0.1161 LY | 140.4 AU | 12,278.6 AU | 31.881% GW0 |
18 days | 139.76 AU/dy | 80.72% c | 7,203.9 AU | 0.1139 LY | 139.8 AU | 12,418.3 AU | 32.105% GW0 |
Given |
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| dt-1 - dt | dΔ + ΣdΔ | 1-(1-ε∇)100+t |
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Decel.
Time(t) | Spot
Velocity (Vt) | Spot
Distance (dt) | Daily
Dist. (dΔ) | 7G
Dist.(d7G) | Total
Fuel (F) |
19 days | 139.08 AU/dy | 80.32% c | 7,064.8 AU | 0.1117 LY | 139.1 AU | 12,557.5 AU | 32.327% GW0 |
20 days | 138.38 AU/dy | 79.92% c | 6,926.4 AU | 0.1095 LY | 138.4 AU | 12,695.9 AU | 32.549% GW0 |
21 days | 137.67 AU/dy | 79.51% c | 6,788.7 AU | 0.1073 LY | 137.7 AU | 12,833.6 AU | 32.770% GW0 |
22 days | 136.95 AU/dy | 79.10% c | 6,651.7 AU | 0.1052 LY | 137.0 AU | 12,970.6 AU | 32.990% GW0 |
23 days | 136.21 AU/dy | 78.67% c | 6,515.4 AU | 0.1030 LY | 136.3 AU | 13,106.9 AU | 33.210% GW0 |
24 days | 135.46 AU/dy | 78.24% c | 6,379.9 AU | 0.1009 LY | 135.5 AU | 13,242.4 AU | 33.428% GW0 |
Given |
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| dt-1 - dt | dΔ + ΣdΔ | 1-(1-ε∇)100+t |
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After 684 days of mission time, resupply vessel flight profile used 7G acceleration and high speed cruise to reach a position 58,340 AU from Sol.
At this point, 7G vessel is only 1,076 AU behind the 1G vessel.
The 7G vessel must start the 48¼ days of 7G deceleration required to slow down from 149.9 AU/day to 111.5 AU/day, cruise velocity of the primary vessel.
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For functional rendezvous, both the primary mission vessel and the resupply vessel must match velocities at the same position at the same time.
In this example, both vessels simultaneously reach 64,796 AU (about one LY) along the track from Sol to neighboring star.
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Determine Intersection Point
Assume the 1G pax vessel accelerates at 1G for one year; then, cruises at constant velocity. Thus, determine distance traveled per following linear equation:
d1G = -.267 LY + .644 c × t
Assume resupply vessel starts 7G accelerates at 265.25 days after mission vessels begins. 100 days later (365.25 days into mission), 7G vessels stops acceleration and starts cruise. Thus, determine total distance traveled via following linear equation:
d7G = -.711 LY + .866 c × t
To determine intersection point of the two linear equations, set them equal as shown:
d1G = -.267 LY + .644c × t = -.711 LY + .866c × t = d7G
For convenience, substitute following terms: LY = 63,241 AU and c = 173.15 AU/day:
-16,885 AU + 111.5 AU/day × t = -44,964 AU + 149.9 AU/day × t
thus, solve for: tInt = 731.2 days and dInt= 64,644 AUs.
These linear equations enable us to determine that the two cruising vessels will meet at time equals 731.2 days (2 years) since day zero and distance equals 64,644 AU (about 1 LY) from 1G pax vessel's starting point. However, the two vessels cannot gracefully rendezvous because they still have a huge velocity differential of about .22 c. A following section proposes a deceleration method to synchronize velocity in addition to time and distance.
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Decel.
Time(t) | Spot
Velocity (Vt) | Spot
Distance (dt) | Daily
Dist. (dΔ) | 7G
Dist.(d7G) | Total
Fuel (F) |
25 days | 134.70 AU/dy | 77.79% c | 6,245.1 AU | 0.0988 LY | 134.8 AU | 13,377.2 AU | 33.646% GW0 |
26 days | 133.91 AU/dy | 77.34% c | 6,111.1 AU | 0.0966 LY | 134.0 AU | 13,511.2 AU | 33.864% GW0 |
27 days | 133.12 AU/dy | 76.88% c | 5,977.9 AU | 0.0945 LY | 133.2 AU | 13,644.4 AU | 34.080% GW0 |
28 days | 132.30 AU/dy | 76.41% c | 5,845.5 AU | 0.0924 LY | 132.4 AU | 13,776.8 AU | 34.296% GW0 |
29 days | 131.47 AU/dy | 75.93% c | 5,713.9 AU | 0.0904 LY | 131.6 AU | 13,908.4 AU | 34.512% GW0 |
30 days | 130.62 AU/dy | 75.44% c | 5,583.1 AU | 0.0883 LY | 130.7 AU | 14,039.1 AU | 34.726% GW0 |
Given |
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| dt-1 - dt | dΔ + ΣdΔ | 1-(1-ε∇)100+t |
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Decel.
Time(t) | Spot
Velocity (Vt) | Spot
Distance (dt) | Daily
Dist. (dΔ) | 7G
Dist.(d7G) | Total
Fuel (F) |
31 days | 129.76 AU/dy | 74.94% c | 5,453.2 AU | 0.0862 LY | 129.9 AU | 14,169.0 AU | 34.940% GW0 |
32 days | 128.88 AU/dy | 74.43% c | 5,324.2 AU | 0.0842 LY | 129.0 AU | 14,298.1 AU | 35.153% GW0 |
33 days | 127.98 AU/dy | 73.91% c | 5,196.1 AU | 0.0822 LY | 128.1 AU | 14,426.2 AU | 35.366% GW0 |
34 days | 127.06 AU/dy | 73.38% c | 5,068.9 AU | 0.0802 LY | 127.2 AU | 14,553.4 AU | 35.577% GW0 |
35 days | 126.13 AU/dy | 72.84% c | 4,942.6 AU | 0.0782 LY | 126.3 AU | 14,679.7 AU | 35.788% GW0 |
36 days | 125.17 AU/dy | 72.29% c | 4,817.3 AU | 0.0762 LY | 125.3 AU | 14,805.0 AU | 35.999% GW0 |
Given |
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| dt-1 - dt | dΔ + ΣdΔ | 1-(1-ε∇)100+t |
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Decel.
Time(t) | Spot
Velocity (Vt) | Spot
Distance (dt) | Daily
Dist. (dΔ) | 7G
Dist.(d7G) | Total
Fuel (F) |
37 days | 124.20 AU/dy | 71.73% c | 4,692.9 AU | 0.0742 LY | 124.4 AU | 14,929.4 AU | 36.208% GW0 |
38 days | 123.20 AU/dy | 71.15% c | 4,569.5 AU | 0.0723 LY | 123.4 AU | 15,052.8 AU | 36.417% GW0 |
39 days | 122.19 AU/dy | 70.57% c | 4,447.1 AU | 0.0703 LY | 122.4 AU | 15,175.2 AU | 36.626% GW0 |
40 days | 121.15 AU/dy | 69.97% c | 4,325.7 AU | 0.0684 LY | 121.4 AU | 15,296.6 AU | 36.833% GW0 |
41 days | 120.10 AU/dy | 69.36% c | 4,205.4 AU | 0.0665 LY | 120.3 AU | 15,416.9 AU | 37.040% GW0 |
42 days | 119.02 AU/dy | 68.74% c | 4,086.1 AU | 0.0646 LY | 119.3 AU | 15,536.1 AU | 37.246% GW0 |
Given |
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| dt-1 - dt | dΔ + ΣdΔ | 1-(1-ε∇)100+t |
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Decel.
Time(t) | Spot
Velocity (Vt) | Spot
Distance (dt) | Daily
Dist. (dΔ) | 7G
Dist.(d7G) | Total
Fuel (F) |
43 days | 117.92 AU/dy | 68.11% c | 3,968.0 AU | 0.0627 LY | 118.2 AU | 15,654.3 AU | 37.452%GW0 |
44 days | 116.80 AU/dy | 67.46% c | 3,850.9 AU | 0.0609LY | 117.1 AU | 15,771.4 AU | 37.657%GW0 |
45 days | 115.66 AU/dy | 66.80%c | 3,735.0 AU | 0.0591 LY | 115.9 AU | 15,887.3 AU | 37.861%GW0 |
46 days | 114.49 AU/dy | 66.12% c | 3,620.2 AU | 0.0572 LY | 114.8 AU | 16,002.1 AU | 38.065%GW0 |
47 days | 113.30 AU/dy | 65.44% c | 3,506.6 AU | 0.0554 LY | 113.6 AU | 16,115.7 AU | 38.268%GW0 |
48 days | 112.09 AU/dy | 64.74% c | 3,394.2 AU | 0.0537 LY | 112.4 AU | 16,228.0AU | 38.470%GW0 |
Resupply Vessel Matches Cruise Velocity of Baseline "Pax" Vessel (1.0 yr of 1G Accel.)
at exactly the time/distance of the intercept. |
48¼days | 111.78 AU/dy | 64.56% c | 3,366.3 AU | 0.0532 LY | 27.9 AU | 16,256.0 AU | 38.520%GW0 |
Given |
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| dt-1 - dt | dΔ + ΣdΔ | 1-(1-ε∇)100+t |
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Decel.
Time(t) | Spot
Velocity (Vt) | Spot
Distance (dt) | Daily
Dist. (dΔ) | 7G
Dist.(d7G) | Total
Fuel (F) |
52 days | 106.98AU/dy | 61.79%c | 2,966.6 AU | 0.2636LY | 107.3AU | 16,667.7AU | 39.272%GW0 |
53 days | 105.64AU/dy | 61.01%c | 2,860.5AU | 0.2652LY | 106.0AU | 16,773.7AU | 39.471%GW0 |
Resupply Vessel Matches Cruise Velocity of Slower "Pax" Vessel (0.9 yr of 1G Accel.)
at exactly the time/distance of the intercept. |
53.4 days | 105.10AU/dy | 60.70%c | 2,818.4AU | 0.2659LY | 42.0 AU | 16,815.7AU | 39.551%GW0 |
54 days | 104.27AU/dy | 60.22%c | 2,755.7AU | 0.2662LY | 62.6 AU | 16,836.3AU | 39.669%GW0 |
Given |
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| dt-1 - dt | dΔ + ΣdΔ | 1-(1-ε∇)100+t |
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