LEGO Technic Solar System 42254: $99.99, January 1, 2027

What the planet panels say, checked against NASA

Every planet gets a black panel on the base with three numbers: diameter, orbital period and distance from the Sun. We could read five of them in lego.com's images and put them next to NASA's Planetary Fact Sheet (last updated in March 2025).

Ten of the 15 numbers match NASA's figures, including all five diameters. Three orbits run longer than NASA's: Saturn by 9 days (0.08%), Neptune by 176 days (0.29%) and Uranus by 98 days (0.32%). Jupiter's distance is rounded down by half a million km, and Saturn's is 1 million km more (0.07%). We don't know which reference LEGO used. We could not read the Venus, Earth and Mars panels in the images we had.

Why check at all? On Nov 1 the Eurobricks poster R0Sch asked why LEGO can't "take one credible source" for the data, "instead of having again info plaques with errors on them". On the five panels we could read, every gap is under 0.4%. We read them from product images, not from a built set.

Image: The LEGO Group (lego.com)

Analysis: LEGO Technic Solar System or 42179 Earth and Moon?

42179 Planet Earth and Moon in Orbit is the earlier Technic orrery, and Jay's Brick Blog calls 42254 "a larger follow-up" to it. The two sit close on price and pieces, and far apart on what they model.

So $25 buys 46 more pieces and seven more planets, and you lose the Moon. Per piece, 42254 costs 3.2 cents more. LEGO hasn't given 42179 a retirement date, and with Sold out on the page the date matters less than the stock; how to tell if a LEGO set is retiring explains the two labels. Our LEGO Technic sets retiring in 2026 list has 42179 among its 22 sets.

We haven't built either set; build impressions below are quoted from people who have. On accuracy, a 42179 owner answered a buyer who asked how true the gearing is:

Reddit comment by u/MaikThoma on how accurate the LEGO 42179 Earth and Moon gearing is

u/MaikThoma wrote in March 2024 that "the earth rotates 27 times (which should be 28) for the moon to rotate once" and that "The arm will bend, this is not strange, due to the weight." That is one owner, but it shows the kind of rounding a gear orrery makes. 42254's eight planets also sit on long arms.

How close will 42254 be? LEGO only promises the planets move "at their own speeds". In NASA's figures, Mercury laps the Sun about 680 times for each Neptune orbit, by our arithmetic. On Eurobricks, the poster Stereo read a 12-to-16-tooth step between neighbouring rings from the images, a ratio of 1.333. If that reading holds, Mercury would make about 7.5 laps per Neptune lap. Treat it as a forum guess until someone builds the set.

Desk note: Seven of the 25 r/legotechnic search results for "42179" (top sort, read Nov 2) are build-help titles, from "LEGO 42179 Earth not rotating" to "stuck on 42179 (moon and earth in orbit) on bag 1 step 25". On a stack of eight geared rings, check each mesh as you build.

Image: The LEGO Group (lego.com)

If you want a space set before January

These space sets read Available now on lego.com on Nov 2. None is an orrery, but all three can be ordered today.

Pick 42221 if you want Technic gearing and a lower price. Pick 11389 at the same $99.99 as 42254 for an adult: it is marked 18+ and earns 650 Insiders points, which our LEGO Insiders points guide turns into $5 off. 31212, from the Art theme, is the best per-piece value here. For other gifts by budget, see LEGO gifts for adults and the best LEGO sets for adults under $100.

If the orrery itself is the point, print the product page and give the date. Check the page again in December: a Coming soon set can open for pre-order before its date, as 67006 The Marvel Skyline did in October for the same January 1 launch.

GODEEPER: Whether a Sold out set like 42179 tends to come back before it retires, from the 35 sets we tracked. Do Sold Out LEGO Sets Come Back? 6 of 35 Did, Briefly →

Image: The LEGO Group (lego.com)

What fans said in the first two days

The Eurobricks topic reached 44 posts by our Nov 2 read, many of them about gears. One of the warmest lines came from dhc6twinotter on Nov 1: "This is the first “must buy” technic set I’ve seen in the past several years." Under Jay's Brick Blog's post, Natalie gave a different reason: "I love Technic but hate cars and vehicles, so I’m super keen for this set." If you do want the cars, our best LEGO car sets for adults covers all 28 marked 18+.

The price drew the opposite view. Prequelfan wrote "$100 for this is pretty high", and sami replied: "agreed, for ~600 pieces the Lego tax is pretty steep with this set". On Eurobricks, Meaf wanted a bigger Sun. Those are a handful of commenters in two threads, so read them as the first reactions, not a verdict.

Our take

Wait for January 1 and buy 42254 if you want an orrery for a desk or shelf. It models all eight planets for $25 more than 42179, and 42179 reads Sold out with the badge on.

Buy now if you need a space set under the tree: 42221 at $59.99 or 11389 at $99.99 can be ordered today. Wait if the orrery is the gift; there is nothing to order yet.

What we don't know yet: the real gear ratios, the Insiders points figure, and whether pre-orders open before January 1. On our watchlist: we re-check the 42254 page each week until launch, and on launch day.

This take uses only the lego.com data and sources cited above, checked Nov 2.

How we checked this

We read the lego.com US pages for 42254, 42179, 11389, 31212 and 42221, the Space page and the Canadian 42254 page in a browser on the afternoon of Nov 2 (US time), and the product page data behind them. Panel numbers come from lego.com's own images, compared with NASA's Planetary Fact Sheet. Per-piece figures are list price divided by pieces. Brickset blocked our browser, so 572 pieces is lego.com's count, matched by The Brick Fan and Jay's Brick Blog. We haven't built the set.

Frequently Asked Questions

Is the LEGO Technic Solar System set motorized? No motor is mentioned. The lego.com description of 42254 names a hand-cranked gear mechanism and lists no motor or battery box. A commenter under Jay's Brick Blog's reveal post asked LEGO to put a motor in the box for an extra $20; LEGO hasn't announced one.

Does LEGO 42254 include Pluto? No. lego.com says 8 planets orbit the Sun, and the rings in LEGO's images run from Mercury to Neptune. Five of the 20 comments under Jay's Brick Blog's reveal post bring up Pluto; one reads "No Pluto No Purchase." Adding it would mean building your own ring and arm.

Does the LEGO solar system set have moons? Not that lego.com shows. Its text names the Sun and 8 planets, and none of the images we looked at has a moon. For the Moon's orbit and its phases you need 42179 Planet Earth and Moon in Orbit, which read Sold out on lego.com on November 2, 2026.

How many LEGO Insiders points will 42254 earn? lego.com shows no figure for 42254 yet. US Insiders earn 6.5 points per dollar, and other $99.99 sets such as 11389 Project Hail Mary list 650 points, worth $5 off a later order. That is the standard rate applied to the price, not a number LEGO has published for this set.

How much is LEGO 42254 in Canada and the UK? CA$129.99 on lego.com's Canadian store, with the same Coming soon on January 1, 2027 note, checked November 2, 2026. Jay's Brick Blog lists £89.99 in the UK and €99.99 in the eurozone. The UK lego.com page did not load for us, so we have not confirmed those two.

Related Reading

• Retired LEGO Technic Sets: 13 Flagships and What Came Next: what happened to earlier Technic sets once lego.com stopped selling them.
• Best LEGO Sets for 8 to 12 Year Olds: 10 Top-Rated Picks: if the 10+ orrery was meant for a child, ten other picks for that age.
• New LEGO Sets 2026: Release Dates, Prices and Early Access: every wave and release date we track, month by month.
• LEGO Sets Retiring in 2026: The Full List by Theme: the full Retiring soon list, with 42179 among the Technic sets.

References

• 42254 Solar System Planets in Orbit on lego.com, The LEGO Group, read November 2, 2026
• 42254 on lego.com Canada, The LEGO Group, read November 2, 2026
• 42179 Planet Earth and Moon in Orbit on lego.com, The LEGO Group, read November 2, 2026
• LEGO Space sets on lego.com, The LEGO Group, read November 2, 2026
• 42221 NASA Artemis Space Launch System Rocket, 11389 Project Hail Mary and 31212 The Milky Way Galaxy on lego.com, read November 2, 2026
• Planetary Fact Sheet, Metric, NASA Space Science Data Coordinated Archive, last updated March 18, 2025
• LEGO Technic 42254 Solar System Planets in Orbit officially unveiled, Jay's Brick Blog, November 1, 2026, and its comments
• LEGO Technic Solar System Planets in Orbit (42254) Officially Revealed, The Brick Fan, November 1, 2026
• Forum topic quoted: 42254 - Solar System Planets in Orbit, Eurobricks, posts of November 1-2, 2026
• Reddit thread quoted: Two questions about Planet Earth and Moon in Orbit set 42179, r/legotechnic, March 2024