A long time ago, I did a limited comparison of our solar system with scaled versions of itself and with Kepler-62. But there are far more systems, and far more places to visit within a star system.

At the risk of being a bit table-spammy, this looks at a more or less complete set of trips between planets around: a G-dwarf (Sol), a K-dwarf (Kepler-62), an early M-dwarf (L98-59), and an ultracool dwarf (TRAPPIST-1).

The plotted trips consist of:

Traveling from a planet’s surface to a circular 200 km orbit. Three different values are considered: orbital speed at that altitude, an idealized 2 burn trasfer from the surface, and 20% more ΔV than circular velocity. This 20% figure is a rather arbitrary (and possibly pessimistic) way of considering atmospheric and gravity losses, but is at least consistent and should be vaguely accurate. The 200 km altitude is also arbitrary (if perhaps optimistic), but works as a parking orbit for Earth. Assuming thin atmospheres and/or low scale heights, it can be applied elsewhere. I’ll try to note planets where this is silly (eg: gas giants)
Hohmann transfers are performed to travelling between planets. Yes, this implies circular coplanar orbits. For the chosen systems, this is usually “good enough”.
I include the Oberth effect in the typical patched conic way (orbit goes from the nominal SOI edge to 200 km altitude).
Typical transfer and wait times are considered, but overall Δv is not added up. Just note that starting a transfer from body x to body y is the same as ending one from body y to body x (assuming no aerobraking).

Gravity assists and travel times/Δv for eg: brachistochrones are also being ignored. Things are complicated and messy enough even in the simple cases, and this is a relatively simple comparsion.

Transfer and wait times are symmetric. Transfer ΔVs are not. Start with a column, and go down to the row with your destination.

The raw spreadsheet(s), including some systems that were ultimately ignored

Our solar system

Body	Mercury	Venus	Earth‡	Mars‡	Jupiter	Saturn	Uranus	Neptune
Mass (kg)	3.301E+23	4.868E+24	5.972E+24	6.417E+23	1.898E+27	5.683E+26	8.681E+25	1.024E+26
Radius (m)	2.440E+06	6.052E+06	6.371E+06	3.390E+06	6.991E+07	5.823E+07	2.536E+07	2.562E+07
Semi-major axis (au)	0.39	0.73	1.00	1.52	5.20	9.58	19.19	30.07
Orbital period (yr)	0.24	0.62	1.00	1.88	11.87	29.66	84.07	164.89
Orbital speed (m/s)	47872	34903	29785	24129	13057	9622	6799	5432
SOI (m)	1.124E+08	6.204E+08	9.246E+08	5.772E+08	4.821E+10	5.481E+10	5.177E+10	8.665E+10
200 km orbit (m/s)	2889	7209	7788	3454	42508†	25479†	15055†	16269†
Ideal Δv (surface to 200 km orbit, m/s)	3121	7445	8031	3655	42630†	25566†	15174†	16395†
200 km orbit with 20% margin (m/s)	3467	8650	9346	4145	51010†	30574†	18066†	19522†

Time between launch windows (yr)	Mercury	Venus	Earth‡	Mars‡	Jupiter	Saturn	Uranus	Neptune
Mercury		0.39	0.32	0.28	0.25	0.24	0.24	0.24
Venus	0.39		1.64	0.93	0.66	0.63	0.63	0.62
Earth‡	0.32	1.64		2.14	1.09	1.03	1.01	1.01
Mars‡	0.28	0.93	2.14		2.23	2.01	1.92	1.90
Jupiter	0.25	0.66	1.09	2.23		19.79	13.82	12.79
Saturn	0.24	0.63	1.03	2.01	19.79		45.84	36.17
Uranus	0.24	0.63	1.01	1.92	13.82	45.84		171.53
Neptune	0.24	0.62	1.01	1.90	12.79	36.17	171.53

Transfer time (yr)	Mercury	Venus	Earth‡	Mars‡	Jupiter	Saturn	Uranus	Neptune
Mercury		0.21	0.29	0.47	2.34	5.56	15.31	29.71
Venus	0.21		0.40	0.60	2.55	5.85	15.72	30.21
Earth‡	0.29	0.40		0.71	2.73	6.09	16.04	30.62
Mars‡	0.47	0.60	0.71		3.08	6.54	16.67	31.39
Jupiter	2.34	2.55	2.73	3.08		10.05	21.30	37.03
Saturn	5.56	5.85	6.09	6.54	10.05		27.28	44.14
Uranus	15.31	15.72	16.04	16.67	21.30	27.28		61.12
Neptune	29.71	30.21	30.62	31.39	37.03	44.14	61.12

Transfer Δv (m/s)	Mercury	Venus	Earth‡	Mars‡	Jupiter	Saturn	Uranus	Neptune
Mercury		4487	5523	6577	18121	11197	6917	7184
Venus	5048		3455	3331	17924	11032	6801	7125
Earth‡	7536	3273		2089	17828	10943	6735	7090
Mars‡	10327	4426	3575		17715	10825	6639	7038
Jupiter	15016	7997	6275	4183		10568	6361	6869
Saturn	16048	9031	7261	5545	17591		6267	6795
Uranus	16688	9715	7951	6530	17656	10565		6744
Neptune	16924	9975	8220	6921	17696	10603	6243

There’s nothing really new here, but it’s a good reference.¹ The rescaled variants just add messiness, so are staying in the spreadsheet.

Kepler-62

Kepler-62 is a K2V star with 6 known planets orbiting it. Two of them (Kepler-62 e and Kepler-62 f) are a pair of super-earths with insolations that make them plausibly habitable. The masses are generally poorly measured, with only maximum estimates.² As such, I am using plausible values found via a mass-radius relation³. Specifically, b and c are considered terrestrial, while the rest are neptunian. Even so, Kepler-62 d is the only one that I’m relatively certain is an ice giant.

Kepler 62	b	c	d	e‡	f‡
Mass (kg)	1.528E+25	6.376E+23	2.665E+25	3.199E+25	1.989E+25
Radius (m)	8.355E+06	3.444E+06	1.244E+07	1.027E+07	8.993E+06
Semi-major axis (au)	0.0553	0.0292	0.12	0.427	0.718
Orbital period (yr)	0.0156	0.0341	0.0497	0.3351	0.7318
Orbital speed (m/s)	105208	144784	71420	37861	29198
SOI (m)	8.636E+07	1.280E+07	2.341E+08	8.962E+08	1.246E+09
200 km orbit (m/s)	10917	3417	11863†	14281†	12016
ideal Δv (surface to 200 km orbit, m/s)	11177	3613	12053†	14558†	12281
Δv (200 km orbit w/ 20% margin, m/s)	13100	4101	14235†	17138†	14419

Time between launch windows (yr)	b	c	d	e‡	f‡
Kepler-62 b		0.029	0.023	0.016	0.016
Kepler-62 c	0.029		0.108	0.038	0.036
Kepler-62 d	0.023	0.108		0.058	0.053
Kepler-62 e‡	0.016	0.038	0.058		0.618
Kepler-62 f‡	0.016	0.036	0.053	0.618

Transfer time (yr)	b	c	d	e‡	f‡
Kepler-62 b		0.005	0.016	0.071	0.145
Kepler-62 c	0.005		0.012	0.066	0.137
Kepler-62 d	0.016	0.012		0.086	0.163
Kepler-62 e‡	0.071	0.066	0.086		0.261
Kepler-62 f‡	0.145	0.137	0.163	0.261

Transfer Δv (m/s)	b	c	d	e‡	f‡
Kepler-62 b		17837	10094	13869	12809
Kepler-62 c	12096		19460	17252	14986
Kepler-62 d	12211	35642		9521	9683
Kepler-62 e‡	26832	50049	12299		5376
Kepler-62 f‡	29960	52662	15586	6304

If these look different last time, it’s from using (I think) more accurate masses. While treating the estimate as a point value instead of a distribution is wrong³ (as is arbitrarily picking between the Neptunian and Terran options), it should be considerably better than the very broad lower mass limits:

Planet	b	c	d	e‡	f‡
Radius (\(R_🜨\))	1.31 ± 0.04	0.54 ± 0.03	1.95 ± 0.07	1.61 ± 0.05	1.41 ± 0.07
Maximum (\(M_🜨\))	9	4	14	36	35
Terrestrial (\(M_🜨\))	2.558	0.1068	10.645	5.357	3.330
Neptunian (\(M_🜨\))	2.271	0.5044	4.462	3.223	2.573

L98-59

A less well known M-dwarf system, but also with some rocky planets.⁴ At ~4x the mass of TRAPPIST-1 (M3V vs M8V), it also helps to fill in a gap in my cross-system comparsion.

L98-59	b	c	d	e	f‡
Mass (kg)	2.747E+024	1.194E+025	9.794E+024	1.684E+025	1.672E+025
Radius (m)	5.338E+06	8.476E+06	1.038E+07	9.057E+06	9.121E+06
Semi-major axis (au)	0.0223	0.0309	0.0494	0.0712	0.1052
Orbital period (yr)	0.0062	0.0101	0.0204	0.0351	0.0631
Orbital speed (m/s)	107832	91605	72450	60348	49647
SOI (m)	2.472E+07	6.166E+07	9.106E+07	1.630E+08	2.402E+08
200 km orbit (m/s)	5754	9585	7861	11019	10943
Ideal Δv (surface to 200 km orbit, m/s)	5967	9810	8012	11261	11181
200 km orbit with 20% margin (m/s)	6904	11502	9434	13223	13131

Time between launch windows (yr)	b	c	d	e	f‡
L98-59 b		0.0158	0.0088	0.0075	0.0068
L98-59 c	0.0158		0.0200	0.0142	0.0120
L98-59 d	0.0088	0.0200		0.0487	0.0301
L98-59 e	0.0075	0.0142	0.0487		0.0791
L98-59 f‡	0.0068	0.0120	0.0301	0.0791

Transfer time (yr)	b	c	d	e	f‡
L98-59 b		0.0040	0.0063	0.0093	0.0149
L98-59 c	0.0040		0.0074	0.0107	0.0164
L98-59 d	0.0063	0.0074		0.0137	0.0199
L98-59 e	0.0093	0.0107	0.0137		0.0242
L98-59 f‡	0.0149	0.0164	0.0199	0.0242

Transfer Δv (m/s)	b	c	d	e	f‡
L98-59 b		5168	10675	13013	14388
L98-59 c	5281		5861	9193	11247
L98-59 d	14318	6478		5162	7206
L98-59 e	20487	11217	4330		5045
L98-59 f‡	25761	16005	8105	5104

TRAPPIST-1

Ah, yes. That infamous M8V system with 8 planets, 3 of which are in the habitable zone.⁵

TRAPPIST-1	b	c	d	e‡	f‡	g‡	h
Mass (kg)	6.074E+24	6.904E+24	1.774E+24	4.611E+24	5.578E+24	6.856E+24	1.977E+24
Radius (m)	7.150E+06	6.984E+06	5.000E+06	5.804E+06	6.671E+06	7.322E+06	4.930E+06
Semi-major axis (au)	0.0115	0.0158	0.0223	0.0293	0.0385	0.0469	0.0619
Orbital period (yr)	0.0041	0.0066	0.0111	0.0167	0.0252	0.0338	0.0514
Orbital speed (m/s)	82686	70655	59528	51925	45265	41039	35704
SOI (m)	2.829E+07	4.078E+07	3.336E+07	6.425E+07	9.124E+07	1.205E+08	9.685E+07
200 km orbit (m/s)	7426	8009	4771	7159	7361	7799	5071
Ideal Δv (surface to 200 km orbit, m/s)	7633	8236	4960	7404	7580	8011	5275
200 km orbit with 20% margin (m/s)	8912	9610	5725	8591	8833	9359	6085

Time between launch windows (yr)	b	c	d	e‡	f‡	g‡	h
TRAPPIST-1 b		0.0110	0.0066	0.0055	0.0049	0.0047	0.0045
TRAPPIST-1 c	0.0110		0.0165	0.0110	0.0090	0.0082	0.0076
TRAPPIST-1 d	0.0066	0.0165		0.0330	0.0198	0.0165	0.0141
TRAPPIST-1 e‡	0.0055	0.0110	0.0330		0.0495	0.0330	0.0247
TRAPPIST-1 f‡	0.0049	0.0090	0.0198	0.0495		0.0989	0.0495
TRAPPIST-1 g‡	0.0047	0.0082	0.0165	0.0330	0.0989		0.0990
TRAPPIST-1 h	0.0045	0.0076	0.0141	0.0247	0.0495	0.0990

Transfer time (yr)	b	c	d	e‡	f‡	g‡	h
TRAPPIST-1 b		0.0008	0.0011	0.0015	0.0020	0.0025	0.0035
TRAPPIST-1 c	0.0008		0.0013	0.0017	0.0022	0.0028	0.0038
TRAPPIST-1 d	0.0011	0.0013		0.0021	0.0027	0.0032	0.0043
TRAPPIST-1 e‡	0.0015	0.0017	0.0021		0.0031	0.0037	0.0049
TRAPPIST-1 f‡	0.0020	0.0022	0.0027	0.0031		0.0044	0.0056
TRAPPIST-1 g‡	0.0025	0.0028	0.0032	0.0037	0.0044		0.0063
TRAPPIST-1 h	0.0035	0.0038	0.0043	0.0049	0.0056	0.0063

Transfer Δv (m/s)	b	c	d	e‡	f‡	g‡	h
TRAPPIST-1 b		3767	7286	8923	10280	10808	12099
TRAPPIST-1 c	3540		3376	5653	7316	8182	9623
TRAPPIST-1 d	7767	3775		3150	4584	5603	6905
TRAPPIST-1 e‡	11248	6237	2560		3148	4015	4881
TRAPPIST-1 f‡	14416	8945	4947	3072		3077	3197
TRAPPIST-1 g‡	16410	10798	6810	4033	2879		2364
TRAPPIST-1 h	18845	13179	9332	5749	3827	3229

Final Thoughts

TRAPPIST-1 is the only system where the transfer Δvs don’t seem to jump enormously when compared with Sol’s. I think this shows the planets being tightly packed and low mass when compared with the others. The planet masses have a huge effect in terms of getting to orbit also, dominating over transfer numbers if one plans to land. This might mean that most places are actually harder from an interplanetary travel perspective than Earth, but could also be observation bias.

Transfer times and transfer window frequency are more or less monotonic with stellar mass^-1. Likewise SOI sizes. Planet orbital speeds aren’t quite, but that’s in part because of how the distributions of the 4 systems vary.

Mission times could potentially be in ‘easy’ reach, being no more than some proposed lunar missions or actual space station ones, though how that interacts with the Δv numbers for Kepler-62 and L98-59 would require far more detailed analysis that I feel like doing. Maybe Project Rho has some useful heuristics.

It was surprisingly hard to find good exo-earth analogs. I know that we’ve found far more hot jupiters and neptunes, but still… (eg: Kepler-90 was initially intriguing, but the planets closest to having reasonable instellations were gas giants. Similarly, all of Kepler-80’s planets are also quite hot)

† Planet is (or probably is) a gas or ice giant, so don’t take these figures too seriously.

‡ Planet is or may be relatively habitable.

Data Sources

Wikipedia, as the solar system bodies are generally known well to high precision. ↩
The 2013 discovery paper for Kepler-62 ↩
Probabilistic Forecasting of the Masses and Radii of Other Worlds ↩ ↩²
The 2025 discovery of a 5th planet around L98-59 ↩
A 2018 update on the masses of the TRAPPIST-1 planets, and a 2017 study of TRAPPIST-1 with Spitzer data for their periods and the star’s properties. ↩