Android Hardware Phones Reviews

Astro Slide review first look: does this device deliver on the Psion Series 5 phone promise?

Astro Slide review

If you’re already familiar with the Gemini PDA and the Cosmo Communicator, both created by UK-based Planet Computers, then you’ll recognise the Astro Slide for the evolution it is. Take one Psion Series 5 keyboard, add a screen, and you have a pocket computer in the truest sense.

And unlike the Gemini and the Cosmo, the Astro Slide hides the keyboard under the screen, so you can just use it as a normal phone. Below, I’ve included a GIF showing the opening mechanism that I took from GSM Arena’s original article – even though this was created last year, it’s still accurate.

We had an exclusive briefing with Dr Janko Mrsic-Flogel, the CEO and founder of Planet Computers, in the company’s central London office where we had a chance to not only quiz him on the latest developments but spend some time playing with the Astro Slide itself. Here are our first impressions of the device, a video of its finest features, and some big questions answered.

Astro Slide video: the best bits

To kick things off, here’s a two-minute video that I recorded after asking Dr Mrsic-Flogel to run through his favourite features:

Astro Slide: what’s the big idea?

Boiled down to the absolutely basics, the Astro Slide is a mid-range Android 11 phone with a full QWERTY keyboard. In its natural state, the keyboard hides underneath the 17.8mm-thick frame, so it’s a beefy slab compared to most phones. Push the ridge of the screen with your thumb, however, and the screen pushes away horizontally before slanting at an angle to create a mini laptop. It’s a clever piece of engineering.

Astro Slide close-up
At 17.8mm thick, this phone clearly has something to hide – in this case a keyboard

An extra trick up its sleeve is support for Linux distributions (this will depend on the various communities to deliver, with Debian likely to arrive first).

Astro Slide keyboard close-up
A close-up of the keyboard, complete with rounded corners and big cursor keys

Software development is one of the keys to the Astro Slide’s attractions. Because there is always a keyboard at the ready, for instance, you can type “backup” and activate a search across the web, the settings and local storage simultaneously. We’ll come back to this.

Astro Slide specifications (final)

Here’s a full list of the Astro Slide’s specifications, which have now been confirmed as final:

  • 8-core MediaTek Dimensity 800 processor (4 x 2.6GHz A76\4 x 2GHz A55 cores, MT6873 SoC)
  • 8GB RAM/128GB storage
  • Backlit physical keyboard
  • Android 11 plus Linux compatibility
  • 6.39in AMOLED screen (2,340 x 1,080 resolution)
  • 5G support (dual SIM 5G + 4G worldwide modem)
  • Wi-Fi 5/Bluetooth 5.1
  • NFC + 10W Qi wireless charging
  • 48MP rear camera/13MP front camera
  • 4,000mAh battery (upgraded from original 3,500mAh specification)
  • 10W Qi wireless charging, 30W fast charging via USB-C
  • 2 x nano SIM slots plus microSD slot
  • 2 x USB-C ports (OTG support, DisplayPort support)
  • 172 x 17.8 x 77mm (WDH)
  • Approx. 300g
Astro Slide specifications
Here’s the official documentation from Planet Computers

Astro Slide keyboard

Planet Computers is rightly proud of the keyboard. Designed by Martin Riddiford, the man behind the Psion Series 5, it shares almost all the same characteristics as that machine’s keyboard. The buttons have a distinct, deep action that means you can type at speed on the Astro Slide if your fingers are nimble enough.

It features a few small tweaks compared to the Cosmo Communicator, as shown in my photo below. Note how the buttons near the corners are rounded and that all the available space is used. The Slide’s keyboard is actually fractionally thinner than that of the Cosmo, but I don’t think you’ll notice this in practice.

Astro Slide keyboard vs Cosmo keyboard
The Astro Slide is on the top, the Cosmo on the bottom

It’s a fully backlit keyboard, too, and can either respond to the ambient lighting conditions or return to a preset level that you set.

The Dimensity question

When Planet Computers announced the Astro Slide it was promising the inclusion of a MediaTek Dimensity 1000 chipset. Reality has unfortunately bitten, however, with the weaker Dimensity 800 making the final cut. This is a mid-range chip that’s roughly equivalent to Qualcomm’s Snapdragon 765G SoC (system on chip).

In our time with the Astro Slide, the Dimensity 800 proved a slick choice. Perhaps some apps would spring into life more quickly with a Dimensity 1000 inside instead, and that more recent chip would have added to its longevity too, but this is one phone where the processor won’t be the thing that defines its success.

Screen and camera

On first look, we like the Astro Slide’s screen (we’ll give it a proper test when the Astro Slide arrives for review). It’s as vivid as we’d expect from any AMOLED screen, and a 2,340 x 1,080 translates into a 403ppi pixel density – it’s sharp.

Planet Computers protects it with a layer of Gorilla Glass (third generation), and avoids the annoyance of a notch by placing the screen in the bezel above the screen.

Astro Slide rear
The rear camera includes a 48MP sensor but it isn’t working fully yet

That’s for the 13MP selfie camera, which falls some way behind the quality of the Apples and Googles of this world but is serviceable for video calls. I have more hope for the rear camera, based as it is on the Sony IMX586 sensor. It’s a big upgrade on the Samsung sensor in the Cosmo, with far richer colours, but with the current firmware it’s stuck at 18MP rather than the 48MP images it’s capable of.

As a result, we saw a lack of detail in images when zoomed in, and found that brickwork was smudged (for example). We hope this will be improved in the final model.

5G support, battery life and repairability

Dr Mrsic-Flogel claims that the Astro Slide prototype downloaded at a peak of 600Mbits/sec when he tested it in Dubai recently, and that in central London (on the Three network) it could hit 430Mbits/sec. Those are respectable speeds, and with the low latency that 5G delivers this should prove to a speedy mobile working device.

Notably, there’s no support for Wi-Fi 6, but NFC is included for Google Pay payments. It also supports wireless charging. Or you can use the USB-C ports, with one on each side.

Battery life will prove interesting to test, with a 4,000mAh unit in place. Not up to the 5,000mAH of the longest-lasting phones, but respectable. We’d hope for a day and a half of usage.

Astro Slide battery
Remove the rear to reveal the replaceable 4,000mAh battery

You could theoretically replace the battery yourself: the plastic rear of the phone unclips easily. However, I would take my unit to a dedicated repair shop that’s equipped with the tools. There’s some delicate cable work involved. You can also replace the screen if it’s cracked, but this involves replacing the entire top of the Slide.

Astro Slide: the built-in software

We asked Dr Mrsic-Flogel about the software enhancements included with the Astro Slide, and his enthusiasm for the updated Airmail software was clear. This now works in portrait view, when you’re using the phone with the keyboard hidden as shown below. You also have the option of a relaxed, compact or neutral view depending on how many emails you want to see on-screen at one time.

Astro Slide Airmail
The improved Airmail software in portrait mode. Flip open the keyboard and it switches to landscape.

From our brief time with it, Airmail looks to be a polished offering (it’s based on an original piece of email software by a Gemini owner before being enhanced by Planet Computers’ in-house developers), which is a relief as this is likely to be one of the key uses of this device. It supports all the usual email services too, including Google and Microsoft.

Planet Computers has also developed its own backup software from the Astro Slide, offering an alternative to anyone who prefers not to share such data with Google. You can backup over a local network (via Samba), USB-C, a microSD card or using the 128GB of built-in storage.

Astro Slide review smart button
Press the “smart button” and you can set an app or a preset action to instantly activate

The final and possibly most handy feature is a smart button on the left-hand side that you can program to launch any app of your choice, or set a series of commands going, or simply tie to one of the preset shortcuts shown in the photo above.

Astro Slide: early verdict

The Astro Slide, for all its cleverness, is a niche device. Few people will want to keep an 18mm phone in a jeans or suit pocket. It’s a pocket computer, but think a winter jacket or cargo pants.

Astro Slide review

There’s a reason why it’s been backed by people from all over the world, though, and that’s its uniqueness. There are other keyboard devices, including the functionally similar Pro 1 X by UK-based F1 Technology. But its keyboard is far more basic, and the company has rebuffed us each time we’ve asked about review samples. This makes it much harder to recommend!

So, should you buy it? If you want to bag one at an Indiegogo price of around £455 then you’ll need to be quick. There’s only one such perk at time of writing, rising to £492 for a lesser perk further down the page. The final price, when it’s formally launched, will be around £799 according to Planet Computers (updated 8 November 2021). Note that pre-orders are due to open on the Planet website from 6 December.

The other question is when you can expect it? There’s still uncertainty here, with final units due to arrive in Hong Kong for quality checking in mid-December. Then they’ll be shipped to the initial backers, so there’s a chance they will get units before Christmas. As for later or new orders…. think spring.

About the author

Tim Danton

Tim Danton is editor-in-chief of PC Pro magazine and has written about technology since 1999. He enjoys playing with gadgets, playing with words and playing tennis. Email

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